Degradable multilayered structures

ABSTRACT

The invention provides a compostable thermoplastic polymer composition comprising a thermoplastic polymer, a transition metal salt selected from cobalt, manganese, copper, cerium, vanadium and iron, and a fatty acid or ester having 10 to 22 carbon atoms providing unsaturated species and free acid. The composition will oxidatively degrade to an embrittled state within at least 14 days at 60° C. and a relative humidity of at least eighty percent. The invention also provides degradable multilayered polyolefin structures incorporating a transition metal in the form of a salt, degradable and compostable multilayered barrier films, degradable, radiation-resistant compositions and articles, and methods of forming and using such compositions, structures and articles.

RELATED APPLICATIONS

This application is a continuation-in-part of pending U.S. patentapplication Ser. No. 07/806,769, filed Dec. 12, 1991, the entirecontents of which are expressly incorporated by reference herein.

FIELD OF THE INVENTION

This invention relates to a novel polymeric blend having enhancedenvironmental degradability properties comprising a non-biodegradablethermoplastic polymer. This invention also relates to multilayeredstructures of non-biodegradable thermoplastic polymers that areenvironmentally degradable, to degradable radiation-resistantcompositions and articles, and to methods of forming and using suchstructures, compositions and articles.

BACKGROUND OF THE INVENTION

There are numerous patents dealing with enhancing the degradability ofconventional non-biodegradable polymers such as polyolefins by use ofadditive systems. These additive systems are quite frequently designedto enhance the polymers degradability in a specific type of environmentand over a specific length of time. For example, U.S. Pat. No. 3,840,512(Brackman) exemplifies prodegradant systems comprising ferric stearatewith various free fatty acids, both saturated and unsaturated. Manganesestearate is also exemplified in a system with stearic acid. Brackmanstates that thermoplastic films (e.g., polyolefin films) formed withthese prodegradant systems will embrittle when exposed to artificiallyUV-activated irradiation at times ranging from 2 to 35 days. It isspecifically stated that the nature of the hydrocarbon group on thefatty acid does not have a large influence on the rate of UVdegradation. Brackman does not address the issue of degradability inother environments, such as in a compost environment. A patent dealingwith a similar prodegradant system, U.S. Pat. No. 4,067,836 (Potts etal.), discloses adding a transition metal salt, an auto-oxidativesusceptible additive, and an anti-oxidant to polyethylene. The onlyexemplified auto-oxidative susceptible additives were polypropylene andpolyethylene oxide (which did not work as acceptably as polypropylene).The degradation of the samples was tested by exposure to an artificialsolar light spectral distribution. The degradability characteristics ofthese prodegradant additives were never demonstrated in otherenvironments such as a compost environment. Generally, additive systemsas described above, designed to make a polymer degrade when exposed toenvironmental radiation, have proved of doubtful practical utility. Onlya relatively small portion of the waste stream is ever exposed tosunlight, even for short periods of time.

In U.S. Pat. No. 3,921,333 (Clendinning, et al.) it is proposed to makethe composition of Potts, et al., discussed above, degradable in a soiltype environment by adding a biodegradable polymer such aspoly(caprolactone). The invention described is allegedly useful formaterials such as transplanting containers, mulch film and the like.Again, only a small portion of the plastic in the waste stream is everused in such environments and as such the compositions described are oflimited applicability based on their limited intended use.

U.S. Pat. No. 4,038,228 (Taylor, et al.) describes placing a transitionmetal salt of an unsaturated organic acid or ester into a polymer film(e.g.,, polyethylene or polypropylene) to enhance its degradability inthe absence of sunlight. The transition metal salts discussed areidentical to many of those exemplified in the above Clendinning et al.and Potts et al. patents; however, they are exemplified at extremelyhigh concentrations. The exemplified film degrades to an embrittledcondition within three days at room temperature. Such a film is ofdoubtful utility as it would likely degrade before use and theexemplified high concentrations of cobalt used would create an extremelycostly and toxic material.

A more recent patent, U.S. Pat. No. 4,931,488 (Chiquet), describes apolymer (e.g., polyethylene) composition which allegedly will degradewhen exposed to heat, ultraviolet radiation, sunlight, or undercomposting conditions. The prodegradant system broadly describedconsists of a biodegradable substance such as starch, an iron compoundand a fatty acid or fatty acid ester, optionally with copper stearate.The exemplified films, however, are limited to polyethylene blended withferric stearate and soya oil, with a minor proportion of cupric stearatein certain examples. Although it is alleged that these compositions aretested under composting conditions, the conditions are not actually setforth and the reported films do not appear to degrade for up to twentyweeks, a situation which would be unacceptable in most commercialcomposting situations where peak temperatures are reached for onlyapproximately two weeks.

As can be seen the art continues to seek to improve the degradability ofconventional plastic films in various environments by use of additiveprodegradant systems. These systems have been designed to providedegradability properties in a wide variety of environmental conditions.Systems that have been found to work in one list of conditions do notnecessarily work under a separate set of conditions which can vary froma dry sunlit exposure to the wet, dark, and relatively infertileconditions of a composter.

Several patents have also dealt with the degradability of multilayeredstructures formed from various polymers. For example, U.S. Pat. No.3,647,111 (Stager et al.) discloses a biodegradable container formedfrom a core layer of an organic filler material, such as peat, and aphenolic resin impregnated with a metallic salt of a fatty acid. Thiscore layer is laminated with an outer protective coating, such as awater-soluble paint, and an inner protective coating, such as a thinplastic liner, a metal flash, or a very thin layer of wax. Allegedly,the extremely thin inner layer, which performs no significant structuralfunction, will break down under normal atmospheric conditions.

U.S. Pat. No. 5,009,648 (Aronoff et al.) discloses biodegradable filmscomprising starch blended with a polymeric material, such as ethylenevinyl acetate, as well as ostomy pouches formed from such films.Supposedly, these films and pouches will degrade when deposited in alandfill or compost heap after transit through a municipal sewage systemand collection at a sewage treatment plant.

Furthermore, U.S. Pat. No. 5,108,807 (Tucker) discloses degradablemultilayer thermoplastic articles comprised of a water-soluble and/orbiodegradable core layer surrounded by two opposing layers ofthermoplastic polymers containing an effective amount of a prodegradant,such that these layers will degrade by photo, thermal, or chemicalmeans. Such articles are disclosed to be useful in the construction ofbags formed from multilayered films.

In a different aspect, considerable research has been conductedregarding the formation of radiation resistant polymeric compositionsand structures. In this regard, attempts have been made to overcomedegradation problems associated with crystalline polypropylene. Forexample, mesomorphous polypropylene, as described in U.S. Pat. No.4,931,230, and articles manufactured from mesomorphous polypropylene,such as described in U.S. Pat. No. 4,950,549, provide resistance tosterilizing irradiation. In addition, polymer blends of mesomorphouspolypropylene and a polymer compatible with such polypropylene, asdescribed in U.S. Pat. No. 5,140,073, have been developed. Bycontrolling the method of preparing mesomorphous polypropylene, throughthe quenching of such polypropylene after hot-melt extrusion, thematerial or articles formed therefrom substantially maintain theirstructural integrity after exposure to ionizing radiation at dosagessufficient to degrade crystalline polypropylene.

Applicants have found a composition which will rapidly degrade underconditions of a typical commercial composting unit yet provide anarticle such as a film which is functional under normal use conditions.A typical composting unit generally is exposed to peak temperatures ofgreater than 60° C. for periods of approximately two weeks or less.During that period, the organic matter in the composter is generallyexposed to an extremely high humidity, generally close to one hundredpercent. These humidity conditions are generally favorable forbiological attack, however, they are generally inhospitable to oxidativetype degradations where transition metal salts are typically employed.

In addition, Applicants have also discovered various multilayerpolyolefin structures that will degrade under a variety of conditions,including the commercial composting conditions described above.Surprisingly, such degradation will occur when one or more of thepolyolefin layers is lacking in a prodegradant system. Also, suchdegradation can surprisingly be accomplished with compositions,articles, and structures formed from radiation resistant, mesomorphouspolypropylene.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a degradable composition comprising athermoplastic polymer, a transition metal salt selected from salts ofcobalt, manganese, copper, cerium, vanadium and iron, and a fatty acidor ester having ten to twenty-two carbon atoms comprised predominantlyof unsaturated species and comprised at least partially of free acid.The composition is designed so that it will oxidatively degrade to forman embrittled polymer within at least fourteen days at 60° C. and at arelative humidity of at least eighty percent. After this peak period,the temperature of a typical compost unit slowly declines, decreasingthe rate of oxidative degradation, often quite dramatically.

The present invention also provides degradable multilayered polyolefinstructures wherein the first layer contains a prodegradant systemcomprised of transition metal salts, and the second layer that does notcontain the prodegradant system. In addition, the present inventionprovides degradable and compostable multilayered barrier films, adegradable, radiation resistant composition, articles formed from suchcompositions, films and structures, as well as methods for containing aperishable material with a degradable packaging film, methods of forminga degradable, radiation-resistant article, and methods of using adegradable multilayered barrier film. All of the multilayered materialsof the present invention will oxidatively degrade to embrittlement at atemperature of about 49° C. over a period of at least about fourteendays. In addition, most of these same materials will also oxidativelydegrade to form an embrittled multilayered structure within at leastabout fourteen days at 60° C. and at a relative humidity of at leasteighty percent.

DEFINITIONS

For the purposes of this invention the definition of "polymer" includesa homopolymer, a copolymer, or an oligomer, as well as any mixtures orblends of one or more homopolymers, and/or one or more copolymers,and/or one or more oligomers.

The term "copolymer" refers to a polymeric material produced by thepolymerization of two or more dissimilar monomers, either with orwithout another functional group, such as maleic anhydride, graftedthereto, as well as to a homopolymer with a functional group graftedthereto. Thus, the term "copolymer" includes, without limitation, randomcopolymers, block copolymers, sequential copolymers, and graftcopolymers.

"Propylene-based material" refers to propylene monomer, or polypropylenepolymer.

The term "moiety" refers to any substance which can be combined with apropylene-based material to forms copolymer, and includes, withoutlimitation, a monomer, a polymer, or a molecule.

"Mesophase propylene-based material", refers to a propylene-basedmaterial, in the ordered, mesophase form, which is neither amorphous,nor so ordered as to constitute the isotactic I crystalline form (e.g.,crystalline polypropylene) as described by G. Natta et al., "Structureand Properties of Isotactic Polypropylene", Del Nuovo Cimento, Suppl.A1, Vol. XV, Serie X, No. 1, 1960, pp. 40-51, the disclosure of which isherein incorporated by reference. A mesophase propylene-based materialis formed by quenching a propylene-based material from the melt state,as defined below, and includes, without limitation, mesomorphouspolypropylene, mesopolymer blends, and/or mesocopolymers, as those termsare defined below.

"Quenching", refers the process of immediately and rapidly coolingpropylene-based material from the melt state such that mesophasepropylene-based material is obtained.

As used herein, "a non-chlorine containing organic polymer which issubstantially impermeable to oxygen gas" refers to polymeric materialswhich are essentially free from chlorine, and which have oxygentransmission rates of less than about 150 cc/m² /day-atmosphere at 25°C. and 0% relative humidity.

"Olefin polymers" or "polyolefins", refers to polymers of theunsaturated hydrocarbons of the general formula C_(n) H_(2n), includingcopolymers of olefins with other monomers such as ethylene with vinylacetate.

"Mesomorphous polypropylene" (mPP) refers to the polypropylenehomopolymer in the mesophase form.

The term "mesopolymer blend" refers to a mixture of mesomorphouspolypropylene with at least one additional polymer (hereinafter a"second polymer").

The term "mesocopolymer" refers to a copolymer of a propylene-basedmaterial an, a discernable amount of at least one moiety that isquenched from the melt state to form a copolymer in the mesophase form.

"Transition metal salt" means any compound or composition containing atransition metal ion and at least one other element. As used herein, atransition metal includes elements 21 through 30, 39 through 48, 57through 80 and 89 through 103 of the Periodic Table, all of which have apartially filled outer shell of electrons.

The terms "degradable", "oxidatively degradable", or "oxidativedegradation" refer to the breakdown of thermoplastic polymers, such aspolyolefinpolymers, to lesser molecular weight components throughoxidative chain scission facilitated by a prodegradant system, as thatterm is defined below. The oxidative degradation of a thermoplasticpolymer also leads to changes in the physical properties of the polymer,such as loss of tensile strength and embrittlement, as that term isdefined below. Generally, a multilayered structure according to thepresent invention is considered to be degradable if it becomesembrittled in the presence of the prodegradant system, when maintainedat a temperature of about 49° C. over a period of approximately fourteendays or less.

"Compostable" refers to the oxidative degradation of thermoplasticpolymers in the warm and moist environment of a municipal or commercialcomposting facility. In general to be considered compostable, apolymeric composition or multilayered structure according to the presentinvention should degrade to embrittlement, as defined below, within atleast about fourteen days at 60° C. and at a relative humidity of atleast about 80 percent. For the purposes of testing the compositions andstructures of the present invention, commercial composting conditionswere simulated by placing single and multilayered films into a Jar ofwater which was then buffered to a pH of 6 by a phosphate buffer andheated to various temperatures.

A "prodegradant system" means any composition of at least one transitionmetal salt that facilitates the oxidative degradation of a thermoplasticpolymers, such as a polyolefin polymer. The prodegradant system may alsooptionally include an auto-oxidative component, as that term is definedbelow. When used to form a compostable thermoplastic polymer orstructure, the prodegradant system will include such an auto-oxidativecomponent.

An "auto-oxidative component" means any substance, compound orcomposition, which in combination with the transition metal salt of theprodegradant system, enhances the oxidative degradation of athermoplastic polymer, such that the polymer is broken down at a fasterrate than if it was contacted with the transition metal salt alone. Whenused to form a compostable polymer and/or structure, the auto-oxidativecomponent includes a fatty acid or ester having ten to twenty-two carbonatoms comprised predominantly of unsaturated species and comprised atleast partially of free acid.

As used herein, "embrittlement" means the point at which samples ofthermoplastic polymers maintained in heated oven or a simulatedcomposting environment either crumble upon folding or creasing, or havelittle or no tear strength remaining. The "time to embrittlement" is thetotal elapsed time from the placement of the samples of degradablepolymers in the oven or simulated composting environment to the point ofembrittlement of the samples.

A "naturally biodegradable polymer" refers to any polymer that issusceptible to breakdown to lesser molecular weight components throughthe action of living organisms, such as bacteria, fungi, and algae.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be further illustrated by reference to theaccompanying Drawings wherein:

FIG. 1 is the wide-angle x-ray diffraction pattern of the film ofExample 152, showing mesomorphous polypropylene containing theprodegradant system of the present invention;

FIG. 2 is the wide-angle x-ray diffraction pattern of the film ofComparative Example 154, showing crystalline polypropylene containingthe prodegradant system of the present invention

FIG. 3 is the wide-angle x-ray diffraction pattern of the multilayeredbarrier film of Example 153; and

FIG. 4 is the wide-angle x-ray diffraction pattern of the multilayeredbarrier film of Comparative Example 155.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

I. Compostable Composition and films

In a first embodiment, the invention is generally directed to acompostable thermoplastic polymer composition comprising a thermoplasticpolymer containing a prodegradant system of an auto-oxidant of anunsaturated fatty acid or ester having ten to twenty-two carbon atoms,and certain transition metal salts.

The fatty acid or ester is present in the polymer composition at aconcentration of about 0.1 to 10 weight percent so as to provide aconcentration of unsaturated species of greater than 0.1 weight percentand a concentration of free acid species greater than 0.1 percent byweight based on the total composition. Further included is a transitionmetal salt at a relatively low concentration of 5 to 500 ppm of themetal itself where the transition metal is selected from the groupcomprising cobalt, manganese, copper, cerium, vanadium and iron,preferably cobalt, manganese, copper or cerium. The composition isformulated such that it will oxidatively degrade, preferably to anembrittled state, within fourteen days at a temperature of about 60° C.and relative humidity of 80 percent or more, preferably 100 percentafter a reasonable shelf life. Generally, it is expected that thecomposition will have to be shelf-stable for a time ranging from oneweek to 12 months. As the degradation occurs slowly, even at roomtemperature, for longer shelf-life products, generally lowerconcentrations of he transition metal or fatty acid (free acid and/orunsaturated species) will be required to provide a compostable film atthe film's intended mean shelf life. Conversely, higher concentrationsof the metal or fatty acid species will be required for films withshort-intended shelf lives.

Thermoplastic polymers suitable for use with the present prodegradantsystem include polyolefins such as polyethylene, polypropylene,polybutylene or poly(4-methyl-1-pentene). Other suitable polymersinclude poly(vinyl acetates), polyesters, polyurethanes, poly(vinylalcohols), polyamides, polystyrenes or polyamines. Copolymers and blendsare also suitable. Preferably, the polymer employed is a saturatedthermoplastic polymer such as polyethylene or polypropylene suitable forextrusion or coextrusion. Most preferred are polypropylenes orpolypropylene blends, such as blends of polypropylene andpolyethylene-based polymers and copolymers.

The transition metal salts include those discussed, for example, in U.S.Pat. No.. 4,067,836, which salts can be ones having organic or inorganicligands. Suitable inorganic ligands include chlorides, nitrates,sulfates, and the like. Preferred are organic ligands such asoctanoates, acetates, stearates, oleates, naphthenates, linoleates,tallates and the like. Although a wide range of transition metals havebeen disclosed in the art as suitable for various prodegradant systems,for a compostable polymeric film it has been found that the transitionmetal must be selected from the group comprising cobalt, manganese,copper, cerium, vanadium and iron in a concentration range of from 5 to500 ppm and preferably cobalt, manganese, copper and cerium for mostpolymers. Preferably, the transition metal is used in a concentration offrom 5 to 200 ppm which is highly desirable as such metals are generallyundesirable in large concentrations. High transition metalconcentrations in compost material can lead to toxicological andenvironmental concerns due to groundwater leaching of these metals intothe surrounding environment. Further, higher transition metalconcentrations can yield unstable films with the invention prodegradantsystem.

Oxidative degradation in a typical composter occurs under substantiallysaturated atmospheric humidity conditions. The plastic on its externalface will normally see a humidity of approximately 100 percent. Theseare extremely severe conditions for oxidative degradation and it hasbeen found that the prodegradant systems described in the art are notsuitable for adequate degradation of plastics under these conditions.

It is found that adequate degradation under typical compostingconditions requires salts of the above mentioned transition metals incombination with acid moieties such as those found in unsaturated fattyacids. It has also been found that unsaturation in the fatty acid, or anadmixed fatty acid ester or natural oil, is required to produce adequatedegradation with the proper transition metal compound. Preferably, thisunsaturated fatty acid is present in the polymer composition atconcentrations of at least 0.1 weight percent of the composition,preferably at least 0.25 weight percent, and most preferably at least0.5 weight percent. Also suitable are blends of fatty acids and fattyacid esters or oils as long as the amount of free acid and unsaturatedspeckles are generally equivalent to the above described ranges for apure fatty acid containing composition.

Generally, it has been found that unsaturated fatty acids having 10 to22 carbon atoms function well in providing the degradation rate requiredfor a compostable material. Unsaturation such as found in abnormal oilsis found to be preferred. Such unsaturation includes two or more doublebonds in the fatty acid or ester chains. Generally, unsaturation wheretwo of the double bonds are separated by two single bonds, resulting ina doubly allelic carbon atom, has been found to be highly desirable,although conjugated double bonds are also preferred. Samples ofmaterials which contain doubly allelic carbon atoms include linseed oil,linoleic acid and linolenic acid. An example of a common conjugatedfatty acid is eleostearic acid found in high concentration, in the esterform, in natural tung oil. Other natural oils containing fairly highamounts of unsaturation include fish oils such as sardine, cod liver,menhaden, and herring oil. Fatty acids derived from these naturallyoccurring oils containing high percentages of unsaturation are alsosuitable as auto-oxidative accelerating components.

Also suitable are fatty acid derivatives, substituted fatty acids orderivatives or corresponding reduction products such as amines oralcohols and the like, although substitutions should not be adjacent toallelic or conjugated double bonds or other sources of unsaturation asthey tend to reduce the effectiveness of such fatty acids andderivatives. Generally, other acids have been found to be unsuitable,including dicarboxylic fatty acids. However, additive amounts of rosinacids such as Foral™ AX have been found to be useful in some instances.

Preferably, the composition further includes an anti-oxidant.Anti-oxidants help stabilize the polymer during extrusion operationsduring the formation of a film or other article as well as help providea suitable shelf life for the degradable articles. Any suitableanti-oxidants used with the conventional base polymer are acceptableincluding such typical anti-oxidants such as sterically hinderedphenols, aryl amines, thioureas, thiocarbamates, thioesteresters,phosphites, or the like. Illustrative anti-oxidants can be found, forexample, in U.S. Pat. No. 4,067,836. Preferably the anti-oxidant ispresent in a concentration of approximately 0.1 weight percent or morebased on the total polymer composition.

The compostable polymer composition also preferably includes a naturallybiodegradable polymer such as poly(caprolactone), poly(lactic acid),poly(hydroxybutyrate-valerate), poly(ethylene adipate), poly(vinylalcohol), modified starch/oleofin copolymers, poly(propylene oxide), andpoly(ethylene oxide). Other suitable biodegradable polymers aregenerally well known and are described in, for example, U.S. Pat. No.3,921,333. These biodegradable polymers assist in further biodegradationof the composition following the transition metal salt catalyzedoxidative degradation, which reduces the base thermoplastic resin to alower molecular weight substance. Although these biodegradable polymersalone can be broken down fairly rapidly in any compost type environment,their physical properties are generally inferior to those ofconventional thermoplastic films. Further, their costs are often quiteprohibitive for use in typical commercial applications. However, blendedwith conventional thermoplastic materials, such as polyolefins, thesebiodegradable polymers should assist in the biological breakdown of thearticles following the catalytic embrittlement period. Generally, thenaturally biodegradable polymer can be included in amounts from 5 to 50weight percent of the composition, preferably these biodegradablepolymers are used at from 5 to 25 weight percent.

Other conventional additives can be added to the polymer compositionincluding fillers, dyes, pigments, anti-blocking agents or the like.

The invention composition finds particularly advantageous use forproducing films or fibers due to the composition's ability to beextruded without significantly affecting performance. With such extrudedfilms or fibers, the fatty acid species preferably are predominantly C₁₂to C₂₂ species. These fatty acid species are generally more tolerant oftypical extrusion conditions. However, the composition can be used inother extruded articles or non-extruded articles.

Typical uses for the composition as extruded films or fibers includedisposable items which would in use be at ambient conditions or below,or exposed to elevated temperatures for a relatively short period oftime. This would include trash bags, disposable diaper components (e.g.,diaper backsheets, polymer film components, extruded nonwoven fiberwebs, and the like), freezer bags, disposable medical bags orcomponents, disposable garments, hygiene articles, internal packagingfilms, etc.

II. Degradable Compositions and Articles, Multilayered StructuresMethods of Formation and Use

In a second embodiment, the invention is directed to degradablecompositions, articles, and structures, including compostable materials,comprising polyolefin polymers containing a prodegradant system oftransition metal salts. The transition metal salt of the prodegradantsystem can be any of those defined herein. Preferably, the transitionmetal salt comprises the same salts disclosed in Section I. above, suchas the organic ligand salts of cobalt, manganese, copper, cerium,vanadium, and iron. To facilitate the desired .degradation, thesetransition metals are employed in one or more polyolefin layers atconcentrations of from about 5 parts per million (ppm) to about 2000ppm, more preferably at concentrations ranging from about 25 ppm toabout 500 ppm. When the transition metals are utilized at concentrationsof greater than 500 ppm, an anti-oxidant may be required to maintain anacceptable shelf-life for the resulting product. However, as notedabove, the concentrations of these metal salts should preferably beminimized to avoid toxicological and environmental concerns, and to helpensure acceptable shelf stability for the degradable compositions,structures and articles of the present invention.

The prodegradant system may optionally include an auto-oxidativecomponent, as described in Section I. above. As in the compostablecompositions and films of Section I. of this application, theauto-oxidative component comprises acid moieties such as those found inunsaturated fatty acids or esters. Preferably such fatty acids or esterswill have from 10 to 22 carbon atoms.

When forming a compostable multilayered structure, includingmultilayered barrier and packaging films according to the presentinvention, the prodegradant system will comprise the combination oftransition metal salts and auto-oxidative components, including thepreferred amounts and components disclosed in Section I. of thisapplication. Thus, unsaturated fatty acids having from 10 to 22 carbonatoms, such as oleic acid, linoleic acid, and linolenic acid, as well asnatural oils and fatty acid derivatives, such as linseed oil, tung oil,sardine oil, cod liver oil, and herring oil, comprise desirableauto-oxidative components of the prodegradant system of the presentinvention. As noted above, these unsaturated fatty acids or derivativesare preferably present in one or more polyolefin layers atconcentrations of at least 0.1 weight percent to about 10 weight percentof the composition of that layer, preferably from about 0.25 weightpercent to about 3 weight percent, and most preferably from about 0.5weight percent to about 2 weight percent.

The polyolefin polymers employed in the compositions, structures andarticles of the present invention can include any polyolefins which whencombined with the prodegradant system of the present invention willoxidatively degrade, and/or compost in a suitable environment, ale thoseterms are defined herein. Nonlimiting examples of suitable polyolefinpolymers include polypropylene, polybutylene, polyethylene, low densitypolyethylene (LDPE), linear low density polyethylene (LLDPE), highdensity polyethylene (HDPE), ethylene vinyl acetate copolymer (EVA), andethylene acrylic acid copolymer (EAA). Preferred polyolefin polymers foruse in the degradable compositions, structures and articles of thepresent invention include polypropylene, polyethylene, and polybutylene,with polypropylene and polyethylene being particularly preferred.

In a preferred aspect, the polyolefin polymer of the degradablecompositions, structures, and articles of the present inventioncomprises a mesophase propylene-based material, such as mesomorphouspolypropylene, mesopolymer blends, and/or mesocopolymers. See, copendingand co-filed U.S. patent Ser. Nos. 07/967,837 (Rolando et al.),abandoned 07/968,037 (Wilfong et al.) abandoned, 07/810001 (Wilfong etal.), abandoned, and U.S. Pat. No. 5,140,073, the disclosures of whichare herein incorporated by reference. Even after being exposed to a doseof radiation of from about 1 kGy (0.10 Mrad) to about 200 kGy (20.0Mrad), these mesophase propylene-based materials degrade atsubstantially slower rates than comparable crystalline propylene-basedmaterials. Unexpectedly, degradable compositions, structures, andarticles formed from mesophase propylene-based materials oxidativelydegrade at comparable rates to crystalline propylene-based materialswhen combined with the prodegradant system of the present invention.

For example, the polyolefin polymer used in the degradable materials ofthe present invention may comprise mesomorphous polypropylenehomopolymer, or polymer blends of mesomorphous polypropylene and asecond polymer, that exhibit increased resistance to the degradingeffects of ionizing radiation, including gamma and electron-beamradiation, as described in U.S. Pat. No. 5,140,073. Nonlimiting examplesof suitable second polymers include polybutylene, atactic polypropylene,polypropylene-ethylene copolymers, EVA, EAA, poly(4-methyl pentene), andpolyethylene, including polyethylene copolymers, LDPE, LLDPE, and HDPE.Furthermore, these mesopolymer blends may exhibit other desirableproperties attributable to the second polymers, such as increasedtoughness, heat sealability, softness, and quietness, depending upon theparticular second polymer combined in the mesopolymer blend.

As noted above, the polyolefin component of the degradable compositions,structures, and articles can also comprise a mesocopolymer. In thisregard, any moiety, or combination of moieties, can be used inconjunction with a propylene-based material to form the mesocopolymersused in the materials of the present invention. For example, thepropylene-based material can comprise propylene monomer and the moietyof a different monomer other than propylene, such as ethylene orbutylene, that when polymerized, melt extruded, and quenched, form amesocopolymer.

The mesocopolymers usable in the degradable materials of the presentinvention generally fall within three classes. The first class ofcopolymer comprises a mesocopolymer wherein the other moiety comprises amonomer, such as ethylene or butylene, that is inserted betweenpropylene monomers in a copolymer chain (e.g., Petrothane™ resin No.PP7300-KF (Quantum Chemical, Inc.)). The second class of mesocopolymerscomprise mesocopolymers of the above described class one copolymers,with another moiety grafted to the copolymer chain (e.g., Plexar™ resinNo. 420 (Quantum Chemical, Inc.)). The third, and final, general classof mesocopolymers comprise a mesomorphous polypropylene homopolymer witha moiety, such as maleic anhydride or acrylic acid, grafted to thepolymer chain (e.g., Admer™ resin No. QF551A (Mitsui Plastics, Inc.)).

The combination of a mesophase propylene-based material with theprodegradant system provides a unique composition according to thepresent invention.. As described above, mesophase propylene-basedmaterials, such as mesomorphous polypropylene, mesopolymer blends, ormesocopolymers, formed by quenching propylene-based materials from themelt state, are significantly more resistant to degradation by ionizingradiation than a comparable material or structure formed from acrystalline propylene-based material. See also U.S. Pat. Nos. 4,931,230,4,950,549, and 5,140,073, and U.S. patent applications Ser. Nos.07/967,837 abandoned and 07/968,037, abandoned. Surprisingly, thesedegradation resistant, mesophase propylene-based materials oxidativelydegrade and/or compost when combined with the prodegradant system of thepresent invention. Even more surprisingly, these degradation resistantmaterials degrade and/or compost at essentially the same rates ascomparable crystalline propylene-based materials. Furthermore, suchdegradation and/or composting functions equally well for mesophasepropylene-based materials lacking the prodegradant system that arelayered or in contact with another polyolefin layer containing theprodegradant system of the present invention.

The degradable, radiation resistant composition of a mesophasepropylene-based material with the prodegradant system can be formed viamelt extrusion, followed by quenching, into a number of useful articles,such as films, fibers, tubes, and microfibers. These articles can inturn be manufactured into, or be used as a component part of, additionaluseful structures, such as tapes, multilayered barrier and packagingfilms, a transdermal drug delivery patch, or an ostomy pouch.

The degradable compositions, structures, and articles of the presentinvention may also optionally contain additional conventional additives,including fillers, dyes, pigments, anti-blocking agents, plasticizers,and the like, as described in Section I. of this application. Of theseadditives, it is often preferable that these degradable materialsinclude an anti-oxidant to help stabilize the structures or articles,particularly with respect to shelf life. Preferred anti-oxidants includethose described above in Section I. of this application.

Furthermore, the degradable materials of the present invention may alsoinclude naturally biodegradablepolymers, such as poly(caprolactone) andpoly(lactic acid), as described in Section I. above. These naturallybiodegradable polymers can either be blended with the degradablecompositions into one or more of the layers of the structures of thepresent invention, or can be included as one or more separate anddistinct layers in a multilayered construction. When used as the gasbarrier layer of degradable and compostable barrier films according tothe present invention, the naturally biodegradable polymers willtypically comprise ethylene vinyl alcohol copolymer (EVOH) and/orpolyvinyl alcohol (PVOH).

In their most basic form, the degradable multilayered structures of thepresent invention comprise a first polyolefin layer containing theprodegradant system contacting a second polyolefin layer without theprodegradant system. However, it is within the scope of the presentinvention to provide a degradable and/or compostable structure ofvirtually any combination or one or more polyolefin layers with theprodegradant system with one or more layers without the prodegradantsystem. Thus, a structure of a polyolefin layer containing theprodegradant system sandwiched between two polyolefin layers lacking theprodegradant system, as well as other structures, is within the presentinvention. As long as such structures degrade and/or compost within theconditions described herein, they are considered to fall within thepresent invention.

The polyolefins utilized in these multilayered structures can comprisethe same polyolefin in all layers, or different polyolefins, includingblends and copolymers, in various layers. In addition, some or all ofthe layers can be comprised of mesophase propylene-based materials suchas mesomorphous polypropylene, mesopolymer blends, and/ormesocopolymers. Furthermore, naturally biodegradable polymers can beblended into one or more layers, and/or appear as separate and distinctlayers of these degradable multilayered structures.

The thickness of the various layers of these multilayered structures canbe widely varied, and still provide a degradable and/or compostableStructure according to the present invention. In this regard, the ratioof the thickness of a layer containing the prodegradant system to thethickness of a layer without the prodegradant system can be from about1:10 to about 1000:1, more preferably from about 1:2 to about 100:1, andmost preferably from about 1:1 to about 10:1.

In a preferred embodiment, the degradable multilayered structureaccording to the present invention comprises a degradable multilayeredbarrier film of a gas barrier layer of a chlorine-free, naturallybiodegradable polymer and one or more moisture barrier layers ofmesophase propylene-based materials containing the prodegradant systemof the present invention. In this regard, any mesophase propylene-basedmaterial, such as mesomorphous polypropylene, mesopolymer blends,mesocopolymers, or combinations thereof, can serve as moisture barrierlayers that protect the gas barrier layer from moisture that wouldreduce or eliminate its gas and odor impeding properties.

For example, the degradable barrier film may be comprised of a layer ofa chlorine-free, naturally biodegradable copolymer, such as EVOH,contacted on opposing sides by moisture barrier layers of mesomorphouspolypropylene containing the prodegradant system of the presentinvention. In addition, such a structure may also contain optionaladhesive layers, such as an Admer™ adhesive resin in a mesophase form,interposed between the gas barrier layer and moisture barrier layers toprovide additional structural integrity to the overall barrier film.However, it will be appreciated that any degradable multilayered barrierstructure with two or more layers, which includes at least one gasbarrier layer, and at least one moisture barrier layer, is considered tobe within the present invention.

The gas barrier layer of the degradable multilayered barrier film iscomprised of a chlorine-free, naturally biodegradable polymer which issubstantially impermeable to oxygen gas. Preferably, the chlorine-freenaturally biodegradable polymer exhibits a permeability to oxygen (O₂)gas of less than 100 cc/m² /day-atmosphere (hereinafter expressed as"cc/m² /d-atm"), more preferably less than 30 cc/m² /d-atm, and mostpreferably less than 5 cc/m² /d-atm, where the permeability measurementsare taken at 25° C. and zero percent (0%) relative humidity. It willalso be appreciated that the O₂ permeability measurements are expressedfor a multilayered barrier film with a gas barrier layer thickness of25μ (microns). Accordingly, appropriate adjustment of the permeabilityvalues must be made, depending upon the thickness of the gas barrieremployed in a structure, as well as the number of gas barrier layersutilized therein. In either case, the values should be normalized to atotal gas barrier layer thickness of 25μ. All values were normalized tostandard gas barrier layer thickness of 25μ by multiplying the oxygentransmission rate value by the ratio of barrier layer thickness to 25μ.In addition to substantial impermeability to O₂ gas, it will further beappreciated that the gas barrier layer also exhibits barrier propertiesto CO₂, N₂ and H₂ S gases, as well as to other gases and odors.

Nonlimiting examples of suitable chlorine-free, naturally biodegradablepolymers in accordance with the present invention include vinyl alcoholcontaining polymers, such as ethylene vinyl alcohol copolymer (EVOH) andpolyvinyl alcohol (PVOH). Preferably, the chlorine-free polymercomprises EVOH. In this regard, the gas barrier layer should preferablybe comprised of substantially pure EVOH, most preferably comprising 99%or more EVOH. However, it also within the scope of the present inventionto utilize blends of EVOH with other polymers, such as ethylene vinylacetate copolymer.

In another preferred embodiment, the present invention provides acompostable multilayered barrier film of a gas barrier layer of achlorine-free, naturally biodegradable polymer and one or more moisturebarrier layers of polyolefinpolymers containing the prodegradant systemof the present invention. In such an embodiment, the prodegradant systemis specifically comprised of from about 5 ppm to about 2000 ppm of atransition metal in the form of a salt, and an auto-oxidative componentcomprising a fatty acid, substituted fatty acid or derivatives, orblends thereof, having 10 to 22 carbon atoms. This auto-oxidativecomponent comprises between about 0.1 to 10 weight percent based on thetotal composition of the moisture barrier layer(s), and provides atleast 0.1 weight percent of unsaturated species and at least 0.1 weightpercent of free acid species in the total composition. The transitionmetal portion of the salt is selected from the group consisting ofcobalt, manganese, copper, cerium, vanadium and iron.

The polyolefinpolymers used in the moisture barrier layer(s) can be anyof those disclosed herein, including mesophase propylene-basedmaterials, such as mesomorphous polypropylene, mesopolymer blends,mesocopolymers, or combinations thereof. Furthermore, the chlorine-free,naturally biodegradable polymers of the gas barrier layer comprise thesame materials, including the preferred EVOH copolymer described abovefor the degradable multilayered barrier film.

Importantly, the degradable and compostable multilayered barrier filmsof the present invention eliminate chlorine-containing compounds ascomponents of the gas barrier layer, moisture barrier layers, optionaladhesive layers, or as additives to these layers, and thereby provideenvironmentally compatible films that can be disposed of, such asthrough composting, without endangering humans. This is in directcontrast to typical barrier films, using materials such aspoly(vinylidene chloride) (PVDC), and poly(vinyl chloride) (PVC), whichcan present both human and environmental hazards.

In particular, materials such as PVDC and PVC can release hazardoussubstances, such as hydrochloric acid (HCl), polychlorinateddibenzodioxin, and furan toxins into the environment. See e.g., StaffReport, "Proposed Dioxius Control Measure for Medical WasteIncinerators", State of California, Air Resources Board, StationarySource Division, pp. 1-40 (May 25, 1990); Medical Waste PolicyCommittee, "Perspectives on Medical Waste", A Report of the Nelson A.Rockefeller Institute of Government, State University of New York (June,1989). In addition, exposure to di-2-ethylhexylphthalate (DEHP), acommon plasticizer utilized with PVDC and PVC, may present a number ofhealth-related concerns, including reduced blood platelet efficacy, andpotential links to liver cancer. See e.g., Allwood, M. C., "The Releaseof phthalate ester plasticizer from intravenous administration sets intofat emulsion", 29 International Journal of Pharmacology, 233-6 (1986).In contrast, the materials comprising the degradable and compostablemultilayered barrier films of the present invention do not use DEHP, andafter use, are ultimately broken down to environmentally compatiblewater and carbon dioxide.

The articles and multilayer structures of the present invention can beformed by a variety of techniques, including extrusion, coextrusion,lamination, or conventional coating techniques. Preferably, hot-meltcoextrusion is used to form the multilayered structures according to thepresent invention.

Coextrusion is a polymer processing method for bringing diversepolymeric materials together to form unitary layered structures, such asfilms, sheets, fibers, and tubing. This allows for unique combinationsof materials, and for structures with multiple functions, such as,barrier characteristics, radiation resistance, and heat sealability. Bycombining coextrusion with blown film processing, film structures can bemade which have no inherent waste and much lower capital investment overflat film coextrusion. However, flat film processing techniques providean excellent method for making the degradable multilayered films,including barrier films, according to the present invention.

Component polymer or copolymer materials according to the presentinvention can be coextruded from the melt state in any shape which canbe rapidly cooled to obtain a multilayered structures, such as barrierfilms, with a moisture barrier layer which includes mesophasepropylene-based materials. The shape and/or thickness of the coextrudedstructure will be dependent upon the efficiency of the particularextrusion equipment employed and the quenching systems utilized.Generally, films and tubes are the preferred coextruded structures. Onlyunder appropriate, low temperature conditions (i.e., below 60° C.), canmultilayered structures be uniaxially, biaxially or multiaxiallyoriented to further enhances their physical properties without losingthe mesophase form of polypropylene, mesopolymer blends, ormesocopolymers.

To obtain multilayered structures having mesophase propylene-basedmaterials, such as mesomorphouspolypropylene, mesopolymer blends, and/ormesocopolymers, the coextruded structures must be quenched in a mannersuch that the mesophase form of polypropylene and/or mesocopolymer isobtained. Miller, "On the Existence of Near-Range Order in IsotacticPolypropylenes", in Polymer, One, 135 (1960), and U.S. Pat. No.4,931,230, both of the disclosures of which are herein incorporated byreference, disclose suitable methods known to those skilled in the artfor the preparation of mesophase form of polypropylene.

As described by these publications, various known methods of quenchingas soon as possible, and preferably, immediately after extrusion, can beused to obtain a mesomorphous polypropylene homopolymer, mesopolymerblend, and/or mesocopolymer having the mesophase form of polypropyleneand/or mesocopolymer therein. Quenching methods include plunging thecoextruded structure into a cold liquid, for example, an ice water bath(i.e., quench bath), spraying the coextruded structure with a liquid,such as water, hitting the film with a stream of cold air, and/orrunning the coextruded structure over a cooled roll, quench roll, ordrum.

The coextruded multilayered structures of the present invention, such asbarrier or packaging films, are preferably quenched immediately afterextrusion by contact with a quench roll, or by being plunge(into aquench bath. For a film thickness of from about 6μ to about 625μ, wherea quench roll is used, roll temperature is maintained at a temperaturebelow about 38° C., preferably below out 24° C., and the coextrudate isgenerally in contact with the quench roll until solidified. The quenchroll should be positioned relatively close to the coextruder die, thedistance being dependent on the roll temperature, the extrusion rate,the film thickness, and the roll speed. Generally, the distance from thedie to the quench roll is about 0.25 cm to 5 cm. here a quench bath isused, the bath temperature is preferably maintained at a temperaturebelow about 4° C. The bath should be positioned relatively close to thedie, generally from about 0.25 cm to 13 cm from the die to the quenchbath.

The degradable compositions and multilayered structures of the presentinvention will prove particularly useful in a number of manufacturedarticles and structures, such as multilayered packaging films,disposable medical garments, bags, and other components, and varioushygiene articles. Packaging films of a polyolefin layer containing theprodegradant system contacted with one or two polyolefin layers withoutthe prodegradant system could serve to contain various perishableproducts, while at the same time substantially preventing the dispersalof the prodegradant system components into the perishable material. Forexample, a baby bottle liner could be formed from a degradable packagingfilm according to the present invention. In such an instance, theperishable product (i.e. baby formula, juice or water) would be shieldedfrom the prodegradant containing layer of the film by a second layer notcontaining the prodegradant system. After use, such a bottle liner couldbe discarded into a municipal waste stream to be composted or otherwiseoxidatively degraded.

The degradable and compostable multilayered barrier films according tothe present invention will be especially useful in ostomy pouchapplications, where security from odor, integrity of the device, andintegrity of the underlying materials are requirements. Multilayeredbarrier films can be die cut and heat sealed with conventionalequipment, and are compatible with current attachment systems and ostomypouch manufacturing practices. Since the multilayered barrier films aremoisture resistant both inside and out, the resulting ostomy pouch iscapable of being worn during swimming and showering. In addition, otheruseful articles such as tapes, tubings, containers, transdermaldrug-delivery patches and various packaging materials can also be formedfrom the multilayered structures of the present invention.

The degradable and compostable multilayered barrier films of the presentinvention are useful to form or cover a protective environment from anexternal environment, such that moisture and/or gases cannotsubstantially pass through to a perishable product contained therein, ora surface covered thereby. For example, the multilayered barrier filmscan be used to contain a food product or a pharmaceutical product in aprotected environment, to which moisture and/or gases from the externalenvironment cannot substantially pass into. Similarly, the multilayeredbarrier films can comprise a transdermal drug delivery patch, or medicaltape, or an ostomy pouch, which protects the body of a mammal, or thewaste products generated by the mammal, from degradation due to exposureto moisture and/or gases in the external environment.

The following examples are provided to illustrate presently contemplatedpreferred embodiments and the best mode for practicing the invention,but are not intended to be limiting thereof:

TEST PROCEDURES

Embrittlement

Embrittlement was determined by hand testing the samples. A state ofembrittlement was defined as the time at which the samples had little orno tear or tensile strength remaining or would crumble when folded. Withsofter or lower melting polymers, such as polyethylene, the films didnot generally disintegrate or crumble but rather became soft and lostall tensile strength.

Oxidative degradation was tested in dry forced-air ovens maintained atvarious temperatures. Compost conditions were simulated by placing thefilms into a jar of water which was then buffered to a pH of 6 by aphosphate buffer and heated to various temperatures. Samples wereremoved at various times from the dry ovens or simulated compostconditions and tested for embrittlement. Generally, these samples weretested at intervals of 8-24 hours.

Film Preparation

The single layer films of Examples 1-101 were prepared on a 3/4" (1.9cm) HAAKE™ extruder having a L/D ratio of 24:1 using 3 zones havingtemperatures; of 390° F. (199° C.), 410° F. (210° C.), and 430° F. (221°C.) with a die temperature of 430° F. These films were formed on acasting roll at a temperature of 70° F. (21° C.), and were taken off theroll so as to have a total thickness of 4.0 mils (102μ).

The two and three layer films of Examples 102-160 were prepared onconventional extrusion equipment using dual and triple manifoldcoextrusion dies maintained at a melt temperature of 232° C. Thecoextruded films were made at a total thickness of 2.0 mils (51μ), andwere formed on a casting roll maintained at a temperature of 50° C. forthe quenched films, or a temperature of 150° C. for the nonquenchedfilms. The thickness of the respective layers of the two and three layerfilms were varied to determine the effect of layer thickness on overallfilm degradability.

EXAMPLES 1-14

The films were prepared as described above using 566 parts per millionof manganese stearate (i.e., 50 ppm manganese), and 1 weight percent ofthe indicated natural oils (Table 1) in polypropylene (a Shell 5A95 9.5MFI homopolymer with an anti-oxidant available from Shell Chemical Co.,Houston, Tex.) with the exception of Example 14 which utilized 2 percentof a styrene-butadiene rubber (SBR) as an auto-oxidant. The SBR wasincorporated as a concentrate consisting of 28% SBR in 72% Shell 7C04NPP/PE impact copolymer (35 MFI, 9% polyethylene).

Two inch (5 cm) by six inch (15 cm) samples were placed in trays in dryforced air ovens. The trays were removed periodically and the films werecreased by hand. Embrittlement was defined as the point in time when thesamples would first crack and fall apart when creased. In the Tablesprovided the greater than sign indicates that the testing was terminatedat the noted time (in hours). The samples were tested at 60° C., 70° C.,and 88° C. as noted in Table 1 below.

                  TABLE 1                                                         ______________________________________                                                          Time to Embrittlement                                                         (Hours)                                                     Example                                                                              Auto-Oxidant     88° C.                                                                          70° C.                                                                       60° C.                          ______________________________________                                        1      Coconut Oil      55       257   600                                    2      Almond Oil       12       202   317                                    3      Olive Oil        36       202   410                                    4      Castor Oil       55       179   317                                    5      Safflower Oil    31       161   245                                    6      Soy Oil          5        161   291                                    7      Wheat Germ Oil   4.5      161   358                                    8      Walnut Oil       6        130   291                                    9      Dehydrated Castor Oil                                                                          4.5      130   317                                    10     Cod Liver Oil    12       94    190                                    11     Sardine Oil      11       57    149                                    12     Tung Oil         7        53    150                                    13     Linseed Oil      6        20    59                                     14     SBR              26       77    145                                    ______________________________________                                    

All samples were approximately 1-2 weeks old when tested. The tableindicates that the oils containing more highly unsaturated fatty acidesters provide the fastest high temperature degradation at typical dryconditions.

EXAMPLES 15-28

Various films were prepared and tested, as described above for Examples1-14, using 1 weight percent of various fatty acids and fatty acidderivatives as the auto-oxidants. All auto-oxidants were C₁₈ fatty acidsor fatty acid derivatives with 0, 1 and 2 double bonds (stearic, oleicand linoleic, respectively). The samples were approximately 1-2 weeksold when tested. The results are given in Table 2. The results indicatethat substitution of the fatty acid generally does not significantlyeffect the degradation rate of compositions using derivatives of typicalfatty acids.

                  TABLE 2                                                         ______________________________________                                        Example                                                                              Auto-Oxidant      88° C.                                                                         70° C.                                                                       60° C.                          ______________________________________                                        15     Stearic Acid (C18, 0 DB)                                                                        8-23    217   155                                    16     Methyl Stearate   >800    >800  >800                                   17     Ethyl Stearate    >800    >800  >800                                   18     Propyl Stearate   8-23    103   155                                    19     Stearamide        8-23    265   348                                    20     Stearylamine      8-23    >800  >800                                   21     Stearyl Alcohol   8-23    103   204                                    22     Oleic Acid (C18, 1 DB)                                                                          3.5     9-23  48                                     23     Propyl Oleate     8-23    48    120                                    24     Oleamide          30      48    102                                    25     Oleyl Alcohol     8-23    38    102                                    26     Linoleic Acid (C18, 2 DB)                                                                       5.5     23    38                                     27     Methyl Linoleate  10      38    78                                     28     Propyl Linoleate  10      38    116                                    ______________________________________                                    

The examples were also checked for degradation after storing at roomtemperature for 8.5 months. Examples 22 and 24-28 showed signs ofembrittlement, however, Examples 15-21 and 23 were not embrittled atthis date.

EXAMPLES 29-62

Samples were prepared, as described above for Examples 1-14, usingvarious polypropylenes (unstabilized and stabilized, i.e., commerciallyavailable resins with anti-oxidants), stabilized polyethylenes andblends thereof as indicated in Table 3 using the procedure outlinedabove. All metals were added as metal stearates to provide the indicatedconcentration of metal. Samples were then placed in water jars andbuffered to a pH of 6 using a phosphate buffer. The samples were testedfor embrittlement as described above except for the polyethylenes andblends which were tested for softness and loss of tensile strength. Thetime for embrittlement is shown in Table 3 below. The samples weretested within one week after extrusion.

                                      TABLE 3                                     __________________________________________________________________________    Ex.                                     88° C.                                                                     60° C.                                                                     49° C.                 No.                                                                              Composition                          Hrs.                                                                              Hrs.                                                                              Hrs.                          __________________________________________________________________________    29 5A95 PP + 50 ppm Co + 4% Oleic acid, <16 43  85                            30 Unst. PP + 50 ppm Mn + 4% Oleic acid 16  40  85                            31 Unst. PP + 50 ppm Fe + 4% Oleic acid 16  65  88                            32 5A95 PP + 50 ppm Co + 2% Linseed oil + 2% Stearic acid                                                             20  88  140                           33 Unst. PP + 50 ppm Fe + 2% Linseed oil + 2% Stearic acid                                                            40  85  85                            34 5A95 PP + 50 ppm Mn + 4% Oleic acid  40  110 195                           35 Unst. PP + 50 ppm Fe + 4% Stearic acid                                                                             40  134 165                           36 5A95 PP + 50 ppm Mn + 4% Linoleic acid                                                                             42  46  88                            37 5A95 PP + 50 ppm Mn + 2% Linseed oil + 2% Oleic acid                                                               42  96  120                           38 5A95 PP + 50 ppm Mn +  2% Linseed oil + 2% Lauric acid                                                             42  115 190                           39 Unst. PP + 50 ppm Mn + 2% Linseed oil + 2% Stearic acid                                                            42  115 190                           40 5A95 PP + 50 ppm Mn + 2% Linseed oil + Stearic acid                                                                42  195 195                           41 6-166 PP/PE + 50 ppm Mn + 4% Oleic acid                                                                            65  120 195                           42 5A95 PP + 50 ppm V + 2% Linseed oil + 2% Stearic acid                                                              65  195 190                           43 5A95 PP + 50 ppm Mn + 2% Tung Oil + 2% Stearic acid                                                                65  260 595                           44 7C50 PP/PE + 50 ppm Mn + 4% Oleic acid                                                                             88  115 195                           45 7C50 PP/PE + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                               88id                                                                              165 285                           46 Unstabilized 5A95 PP powder (100%)   88  326 400                           47 6180 HDPE + 50 ppm Mn + 2% Linseed oil + 2% Stearic acid                                                           96  235 475                           48 5A95 PP + 50 ppm Fe + 2% Linseed oil + 2% Stearic acid                                                             110 650 >700                          49 1550P LDPE/5A95 PP(77/19) + 50 ppm Mn + 4% Oleic acid                                                              134 231 310                           50 5A95 PP + 50 ppm Ce + 2% Linseed oil + 2% Stearic acid                                                             260 400 >700                          51 1550P LDPE/5A95 PP(77/19) + 50 ppm Mn + 2% Linseed Oil + 2%                                                        260aric                                                                           550 >700                             acid                                                                       52 1550P LDPE + 50 ppm Mn + 4% Oleic acid                                                                             260 >700                                                                              >700                          53 1550P LDPE + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                               305d                                                                              >700                                                                              >700                          54 6180 HDPE + 50 ppm Mn + 4% Oleic acid                                                                              400 >700                                                                              >700                          55 5A95 PP + 50 ppm Mn + 2% Coconut oil + 2% Stearic acid                                                             405 >700                                                                              >700                          56 5A95 PP + 50 ppm Ce + 4% Oleic acid  455 >700                                                                              400                           57 5A95 PP + 50 ppm V + 4% Oleic acid   545 >700                                                                              >700                          58 6-166 PP/PE + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                              575d                                                                              350 > 700                         59 5A95 PP + 50 ppm Mn + 4% β-methylcinnamic acid                                                                >700                                                                              >700                                                                              >700                          60 5A95 PP + 50 ppm Mn + 4% Lauric acid >700                                                                              >700                                                                              >700                          61 5A95 PP + 50 ppm Fe + 4% Oleic acid  >700                                                                              >700                                                                              >700                          62 5A95 PP + 50 ppm Mn + 4% Stearic acid                                                                              >700                                                                              >700                                                                              >700                          __________________________________________________________________________     1 5A95 is Shell 5A95.                                                         2 Unstabilized PP is a 9.0 MFI material available from Shell.                 3 7C50 PP/PB is Shell 7C50, 8.0 MPI and 8% PE.                                4 6180 HDPE is NHD 6180 available from Quantum Co., Rolling Meadows, IL       with an MI of 1.15 and a density of 0.960.                                    5 1550P LDPE is Tenite ™, 3.5 MPI and 8.0 MFI.                             6 6166 PP/PB is random copolymer available fron Shell, and 0.9 density,       available from Hastman Chemical Products, Kingsport, TN.                 

Samples from Examples 29-62 were stored at room temperature forapproximately 1900 hours and checked for embrittlement. Examples 29-41samples showed evidence of embrittlement, while Examples 42-62 samplesshowed no signs of embrittlement.

Table 4 shows the embrittlement time for Examples 29-62 samples in a dryoven.

                                      TABLE 4                                     __________________________________________________________________________    Ex.                                88° C.                                                                     70° C.                                                                     60° C.                                                                     49° C.                  No.                                                                              Composition                     Hrs.                                                                              Hrs.                                                                              Hrs.                                                                              Hrs.                           __________________________________________________________________________    29 5A95 PP + 50 ppm Co. + 4% Oleic Acid                                                                          2   3   9   16                             30 Unst. PP + 50 ppm Mn + 4% Oleic acid                                                                          1   3   7   18                             31 Unst. PP + 50 ppm Fe + 4% Oleic acid                                                                          3.5 11  33  72                             32 5A95 PP + 50 ppm Co + 2% Linseed oil + 2% Stearic Acid                                                        2   9   30  72                             33 Unst. PP + 50 ppm Fe + 2% Linseed Oil + 2% Stearic                                                            4.5 24  85  221                               acid                                                                       34 5A95 PP + 50 ppm Mn + 4% Oleic acid                                                                           2   7   20  48                             35 Unst. PP + 50 ppm Fe + 4% Stearic acid                                                                        6   18  60  143                            36 5A95 PP + 50 ppm Mn + 4% Linoleic acid                                                                        1.5 5   16  40                             37 5A95 PP + 50 ppm Mn + 2% Linseed oil + 2% Oleic acid                                                          2   8   30  54                             38 5A95 PP + 50 ppm Mn + 2% Linseed Oil + 2% Lauric acid                                                         2   7   20  55                             39 Unst. PP + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                            3   9.5 36  94                                Acid                                                                       40 5A95 PP + 50 ppm Mn + 2% Linseed Oil + 2% Stearic acid                                                        2   6   25  54                             41 6-166 PP/PE + 50 ppm Mn + 4% Oleic acid                                                                       6   22  46  97                             42 5A95 PP + 50 ppm V + 2% Linseed oil + 2% Stearic acid                                                         17  84  335 >800                           43 5A95 PP + 50 ppm Mn + 2% Tung oil + 2% Stearic acid                                                           2.5 9   30  90                             44 7C50 PP/PE + 50 ppm Mn + 4% Oleic acid                                                                        3.5 12  37  76                             45 7C50 PP/PE + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                          3   10  36  76                                acid                                                                       46 Unstabilized 5A95 PP powder (100%)                                                                            22.5                                                                              108 385 >800                           47 HDPE + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                                8   34  120 294                               acid                                                                       48 5A95 PP + 50 ppm Fe + 2% Linseed oil + 2% Stearic                                                             53  235 >800                                                                              >800                              acid                                                                       49 1550P LDPE/5A95 PP(77/19) + 50 ppm Mn + 4% Oleic acid                                                         12.5                                                                              169 284 294                            50 5A95 PP + 50 ppm Ce + 2% Linseed oil + 2% Stearic acid                                                        7   34  130 294                            51 1550P LDPE/5A95 PP(77/19) + 50 ppm Mn + 2% Linseed oil                                                        25.5                                                                              114 212 433                               2% Stearic acid                                                            52 1550P LDPE + 50 ppm Mn + 4% Oleic acid                                                                        82  290 60  >800                           53 1550P LDPE + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                          82  470 740 >800                              acid                                                                       54 6180 HDPE + 50 ppm Mn + 4% Oleic acid                                                                         22  47  120 221                            55 5A95 PP + 50 ppm Mn + 2% Coconut oil + 2 Stearic acid                                                         3   16  62  150                            56 5A95 PP + 50 ppm Ce + 4% Oleic acid                                                                           22  24  60  97                             57 5A95 PP + 50 ppm V + 4% Oleic acid                                                                            22.5                                                                              90  165 294                            58 6-166 PP/PB + 50 ppm Mn + 2% Linseed oil + 2% Stearic                                                         4.5 13  51  94                                acid                                                                       59 5A95 PP + 50 ppm Mn + 4% β-methylcinnamic acid                                                           11.5                                                                              185 240 >800                           60 5A95 PP + 50 ppm Mn + 4% Lauric acid                                                                          4   18  62  200                            61 5A95 PP + 50 ppm Fe + 4% Oleic acid                                                                           31  145 335 605                            62 5A95 PP + 50 ppm Mn + 4% Stearic acid                                                                         7   141 40  480                            __________________________________________________________________________

EXAMPLES 63-79

Samples were prepared using various polypropylenes (unstabilized andstabilized commercial polymers), stabilized polyethylenes and stabilizedblends thereof as defined in Table 3 using the procedure outlined above.Samples were then placed in water jars and buffered to a pH of 6 using aphosphate buffer. The samples were tested for embrittlement as describedabove except for the polyethylenes and blends which were tested forsoftness and loss of tensile strength. The time for embrittlement isshown in Table 5 below. The samples were tested soon after extrusion.

                                      TABLE 5                                     __________________________________________________________________________    Ex.                                  88° C.                                                                     60° C.                                                                     49° C.                    No.                                                                              Composition                       Hrs.                                                                              Hrs.                                                                              Hrs.                             __________________________________________________________________________    63 5A95 PP + 50 ppm Mn + 4% Erucic acid                                                                            42  120 185                              64 5A95 PP + 50 ppm Mn + 4% Linseed oil + 2% Euric acid                                                            42  113 190                              65 5A95 PP + 50 ppm Mn + 4% Oleic acid                                                                             45  120 210                              66 Unst. PP + 50 ppm Mn + 4% Oleic acid + 600 ppm Irg. 1010                                                        70  190 210                              67 Unst. PP + 50 ppm Fe + 4% Oleic acid + 600 ppm Irg. 1010                                                        70  190 330                              68 5A95 PP + 50 ppm Mn + 2% Linseed oil + 2% Linolenic acid                                                        95  210 355                              69 5A95 PP + 50 ppm Mn + 4% Linseed oil                                                                            95  190 355                              70 5A95 PP + 50 ppm Mn + 4% Linolenic acid                                                                         165 230 240                              71 1550P LDPE/5A95 PP (66:30) + 50 ppm Mn + 2% Linseed oil                                                         165%                                                                              360 >350                                Stearic acid                                                               72 1550P LDPE/5A95 PP (66:30) + 50 ppm Mn + 4% Oleic acid                                                          190 >350                                                                              360                              73 1550P LDPE/5A95 PP (76:20) + 50 ppm Mn + 4% Oleic acid                                                          210 240 >350                             74 1550P LDPE/5A95 PP (86:10) + 50 ppm Mn + 4% Oleic acid                                                          210 360 >350                             75 1550P LDPE/5A95 PP (76:20) + 50 ppm Mn + 2% Linseed oil                                                         220%                                                                              >350                                                                              >350                                Stearic acid                                                               76 1550P LDPE/5A95 PP (86:10) + 50 ppm Mn + 2% Linseed oil                                                         230%                                                                              >350                                                                              >350                                Stearic acid                                                               77 5A95 PP + 4% Oleic acid           355 210 360                              78 5A95 PP + 50 ppm Mn + 4% Tung Oil 360 >350                                                                              >350                             79 5A95 PP + 50 ppm Mn + 4% Coconut Oil                                                                            >350                                                                              >350                                                                              >350                             __________________________________________________________________________     1 Irganox 1010 is a hindered phenol available from CibaGeigy Co.         

Table 6 shows the embrittlement time for Examples 63-79 samples in a dryoven.

                                      TABLE 6                                     __________________________________________________________________________    Ex.                               88° C.                                                                     70° C.                                                                     60° C.                                                                     49° C.                   No.                                                                              Composition                    Hrs.                                                                              Hrs.                                                                              Hrs.                                                                              Hrs.                            __________________________________________________________________________    63 5A95 PP + 50 ppm Mn + 4% Erucic acid                                                                         3   7.5 25  55                              64 5A95 PP + 50 ppm Mn + 2% Linseed oil + 2% Erucic acid                                                        2   7   28  58                              65 5A95 PP + 50 ppm Mn + 4% Oleic acid                                                                          2   6   21  52                              66 Unst. PP + 50 ppm Mn + 4% Oleic acid + 600 Irg. 1010                                                         3.75                                                                              7.5 26  55                              67 Unst. PP + 50 ppm Fe + 4% Oleic acid + 600 Irg. 1010                                                         23  33  80  123                             68 5A95 PP + 50 ppm Mn + 2% Linseed oil + 2% Linolenic                                                          2.5 8   26  65                                 acid                                                                       69 5A95 PP + 50 ppm Mn + 4% Linseed oil                                                                         3.5 10  34  65                              70 5A95 PP + 50 ppm Mn + 4% Linolenic acid                                                                      2.5 7   23  55                              71 1550P LDPE/5A95 PP (66:30) +  50 ppm Mn + 2% Linseed                                                         20  33  315 244                                oil + 2% Stearic acid                                                      72 1550P LDPE/5A95 PP (66:30) + 50 ppm Mn + 4% Oleic acid                                                       9.5 33  130 148                             73 1550P LDPQ/5A95 PP (76:20) + 50 ppm Mn + 4% Oleic acid                                                       27  100 267 225                             74 1550P LDPQ/5A95 PP (86:10) + 50 ppm Mn + 4% Oleic acid                                                       50  172 320 560                             75 1550P LDPQ/5A95 PP (76:20) + 50 ppm Mn + 2% Linseed                                                          27  123 219 267                                oil + 2% Stearic acid                                                      76 1550P LDPQ/5A95 PP (86:10) + 50 ppm Mn + 2% Linseed                                                          50  130 230 >560                               oil + 2% Stearic acid                                                      77 5A95 PP + Oleic acid           25.5                                                                              90  95  155                             78 5A95 PP + 50 ppm Mn + 4% Tung Oil                                                                            3   16  58  123                             79 5A95 PP + 50 ppm Mn + 4% Coconut Oil                                                                         6   27  99  155                             __________________________________________________________________________

EXAMPLES 80-94

These films (4 mil caliper) were prepared in accordance with Examples1-14 with the exception of Examples 83-89 which were 1 mil films (25.4micrometers). The compositions included various naturally biodegradablepolymers (Tone™ P-700 and Tone™ 767P are poly-e-caprolactones (PCL)available from Union Carbide of Danbury, Conn.; Bipol™ PHBV is apoly(hydroxybutyrate valerate) (12% valerate) available from ICIAmericas, Inc.; Vinex™ 2025 and 2025U are polyethylene/vinyl-alcoholcopolymers available from Air Products & Chemicals, Inc. of Allentown,Pa.; Elvax™ 260 is an ethylene/vinyl acetate copolymer (EVA) (28% vinylacetate and 6 MFI) available from DuPont Co., Wilmington Del.; Nucrel™960 is a polyethylene/methylacrylate copolymer (density=0.94, MFI=60)available from DuPont Co. The poly-L-lactide has an intrinsic viscosityof 1.04 and is available from Birmingham Polymers, Inc. Thepolyesteramide-10,2 (PEA) has an intrinsic viscosity of 0.7 and isavailable from 3M Company, St. Paul, Minn., and Pamolyn™ 100 (PAM) is anoleic acid (91%) available from Hercules, Inc., Wilmington, Del.).

Films from Examples 81 and 82 were tested for degradation in water andair as described above at 60° C. The Example 81 films became embrittledat 43 hours in air and 112 hours in water. The Example 82 films becameembrittled at 53 hours in air and 332 hours in water. The times toembrittlement in air for Examples 83-94 are given in Table 7 below.

                                      TABLE 7                                     __________________________________________________________________________    Ex.                                  88° C.                                                                     70° C.                                                                     60° C.                                                                     49° C.                No.                                                                              Composition                       Hrs.                                                                              Hrs.                                                                              Hrs.                                                                              Hrs.                         __________________________________________________________________________    83 3% POLY-L-LACTIDE + 2% PAM 100    72  465 850 >850                         84 6% POLY-L-LACTIDE + 2% PAM 100    152 370 >850                                                                              >850                         85 9% POLY-L-LACTIDE + 2% PAM 100    80  320 750 >850                         86 9% PEA-10,2 + 2% PAM 100          63  365 >850                                                                              >850                         87 5% PCL + 20% 7C50 + 2% PAM 100    50  130 290 750                          88 5% VINEX 2025U PVA + 20% 7C50 + 2.5% ELVAX 260 EVA +                                                            50  76  225 >850                            2% PAM 100                                                                 89 5% PHBV (12% V) + 20% 7C50 + 2.5% ELVAX 260 EVA + 2%                                                            50  225 490 >850                            PAM 100                                                                    90 20% P700 + 2% PAM 100             6   24  52  100                          91 20% 2025 PVA + 2% PAM 100         60  155 245 370                          92 20% PVA + 10% NUCREL 960 + 2% PAM 100                                                                           50  175 325 465                          93 20% PVA + 10% ELVAX 260 + 2% PAM 100                                                                            225 175 290 465                          94 20% PHBV + 10% ELVAX 260 + 2% PAM 100                                                                           --  --  --  --                           __________________________________________________________________________

    ______________________________________                                        80)      Shell 5A95       88.94%                                                       Tone P-700       10.00%                                                       Tung Oil         1.00%                                                        Manganese (Mn) Stearate                                                                        0.06%                                               81)      Shell 5A95       85.94%                                                       Tone 767P        10.00%                                                       Pamolyn ™ 100 4.00%                                                        Mn Stearate      0.06%                                               82)      Shell 5A95       85.94%                                                       Bipol ™ PHBV  10.00%                                                       Pamolyn ® 100                                                                              4.00%                                                        Mn Stearate      0.06%                                               ______________________________________                                    

Examples 82 was of poor quality because of the incompatibility of PHBVwith polyolefins.

    ______________________________________                                        83)      Tenite ™ 1550P  94.94%                                                     poly-L-lactide     3.00%                                                      Pamolyn ™ 100   2.00%                                                      Mn Stearate        0.06%                                             84)      Tenite ™ 1550P  91.94%                                                     poly-L-lactide     6.00%                                                      Pamolyn ™ 100   2.00%                                                      Mn Stearate        0.06%                                             85)      Tenite ™ 1550P  88.94%                                                     poly-L-lactide     9.00%                                                      Pamolyn ™ 100   2.00%                                                      Mn Stearate        0.06%                                             86)      Tenite ™ 1550P  88.94%                                                     polyesteramide-10,2                                                                              9.00%                                                      Pamolyn ™ 100   2.00%                                                      Mn Stearate        0.06%                                             87)      Tenite ™ 1550P  72.94%                                                     Tone P-700         5.00%                                                      Shell 7C50 PP/PE copolymer                                                                       20.00%                                                     Pamolyn ™ 100   2.00%                                                      Mn Stearate        0.06%                                             88)      Tenite ™ 1550P  72.94%                                                     Vinex ™ 2025U   5.00%                                                      Shell 7C50 PP/PE   17.50%                                                     Elvax ™ 260     2.50%                                                      Pamolyn ™ 100   2.00%                                                      Mn Stearate        0.06%                                             89)      Tenite ™ 1550P  72.94%                                                     Bipol ™ PHBV    5.00%                                                      Shell 7C50         17.50%                                                     Elvax ™ 260     2.50%                                                      Pamolyn ™ 100   2.00%                                                      Mn Stearate        0.06%                                             ______________________________________                                    

EXAMPLES 90-04

(4 mil PP/PE copolymer films)

    ______________________________________                                        90)        Shell 7C50   78.35%                                                           Tone ™ P-700                                                                            19.59%                                                           Pamolyn ™ 100                                                                           2.00%                                                            Mn Stearate  0.06%                                                 91)        Shell 7C50   78.35%                                                           Vinex ™ 2025                                                                            19.59%                                                           Pamolyn ™ 100                                                                           2.00%                                                            Mn Stearate  0.06%                                                 92)        Shell 7C50   68.56%                                                           Vinex ™ 2025                                                                            19.59%                                                           Nucrel ™ 960                                                                            9.79%                                                            Pamolyn ™ 100                                                                           2.00%                                                            Mn Stearate  0.06%                                                 93)        Shell 7C50   68.50%                                                           Vinex ™ 2025U                                                                           19.59%                                                           Elvax ™ 260                                                                             9.79%                                                            Pamolyn ™ 100                                                                           2.00%                                                            Mn Stearate  0.06%                                                 94)        Shell 7C50   82.95%                                                           Bipol ™ PHBV                                                                            10.00%                                                           Elvax ™ 260                                                                             5.00%                                                            Pamolyn ™ 100                                                                           2.00%                                                            Mn Stearate  0.06%                                                 ______________________________________                                    

EXAMPLES 95-98

Films were prepared and tested as described above for Examples 1-14,using unstabilized polypropylene with 2% added Pamolyn™ 100 and 400 ppmFe (as Fe Stearate) at various levels of Irganox™ 1010. The films weretested for embrittlement at various temperatures as indicated in Table 8below.

                  TABLE 8                                                         ______________________________________                                                Irganox ™                                                                             55° C.                                                                         70° C.                                                                        60° C.                                                                       49° C.                         Example (PPM)      Hrs.    Hrs.   Hrs.  Hrs.                                  ______________________________________                                        95      0          4       13     40     96                                   96      200        7.5     34     96    215                                   97      600        20      80     260   650                                   98      1000       39      215    1500  --                                    ______________________________________                                    

The films were also kept on a shelf at room temperature forapproximately 3,900 hours and tested for embrittlement. The Examples 95and 96 films had embrittled at this time, but the Examples 97 and 98films had not.

EXAMPLES 99-101

Immature compost was allowed to dry until it contained only 5% water. To1000 g of this compost were added 200 g of dried, shredded maple leaves,6 g of Compost Plus (Ringer Corporation, Minneapolis, Minn.) andsufficient water to yield of mixture of 54% water. The compost mixturewas placed in a wire mesh basket in a Nalgene tank (Nylon-14"×10"×10"from Fisher) in a forced air oven at 50° C. The compost was aerated fromthe bottom by suspending the wire basket over two glass frits (10"×1.5")in a pool of water through which air was bubbled. The compost mixturecontaining the film sample was piled in the wire basket so that thesamples were completely covered. Several samples could be tested in onesuch apparatus.

The test period was one month. The initial carbon-to-nitrogen ratio ofthe compost mixture was 40:1. The pH of the system remained relativelyneutral, ranging from 5.5-7.0. Moisture was maintained at 45-55% byadding water as necessary. The compost was manually turned daily andfilm samples were checked for embrittlement. Embrittlement was not aspronounced in the simulated compost test as it was in the dry oven testshowever roughly correlated to the water jar test results. Films usuallytore first in one direction, and then both, before becoming brittle.Embrittlement times for Examples 99-101 are listed in Table 9 below.

                  TABLE 9                                                         ______________________________________                                        Example                                                                              Film                  Compost 50° C.                            ______________________________________                                        99     5A95 PP + 50 ppm Co + 4% Oleic                                                                      10 days                                                 Acid                                                                   100    Unstab. 5A95 PP + 50 ppm Mn +                                                                       27 days                                                 4% Oleic acid                                                          101    5A95 PP/Tone ™ 767P PCL                                                                          26 days                                                 (9:1) + 50 ppm Mn + Oleic Acid                                         ______________________________________                                    

EXAMPLES 102-121

Two-layer films were prepared as described above. The first layer ofeach film was approximately 1.75 mil (45μ) thick, and the second layerwas approximately 0.25 mil (6μ) thick, for a total film thickness ofapproximately 2 mil (51μ). A prodegradant system of 2840 parts permillion (ppm) of manganese stearate (i.e. 250 ppm manganese, 50 ppm Mn(568 ppm Mn sterate) for Example film No. 118)(Mooney Chemical,Cleveland, Ohio), and 2 weight percent of Oleic acid (OA)(Kodak ChemicalCo., Rochester, N.Y.) was incorporated into either the first layer orthe first and second layer of the two-layer films. The polyolefinpolymer resins used to form these films included, Shell polypropyleneresin No. 5A95 (Shell Chemical Co., Houston, Tex.), Tenite™ lowdensitypolyethylene resin No. 1550P (Eastman Chemical, Kingston, Tenn.),and Quantum Chemical polyethylene resin No. NA 952 (Quantum Co., RollingMeadows, Ill.).

Two inch (5 cm) by six inch (15 cm) samples of each of the films wereplaced in trays in dry forced air ovens, and were tested forembrittlement at 49° C., 60° C., and 70° C., according to the proceduresof Examples 1-14. In addition, the samples were also placed in waterjars and were tested for embrittlement according to the procedures ofExamples 29-62. The specific composition and time to embrittlement inhours for each of the Example films is shown in Table 10 below. Theletter "Q" indicates films that were formed by quenching at 50° C.,while "NQ" indicates films that were nonquenched by being formed at atemperature of 150° C.

                                      TABLE 10                                    __________________________________________________________________________       Composition of layers        70° C.                                                                     60° C.                                                                     49° C.                                                                     60° C.                     Ex.                                                                              1st layer = 1.75 mil (45μ) thick                                                                        Hrs.                                                                              Hrs.                                                                              Hrs.                                                                              Hrs.                              No.                                                                              2nd layer = 0.25 mil (6μ) thick                                                                         Dry Dry Dry Wet                               __________________________________________________________________________    102                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         17  33  65  270                                  2nd: 5A95 PP (Q)                                                           103                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         17  25  41  270                                  2nd: 5A95 PP (NQ)                                                          104                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          25  33  66  360                                  2nd: 5A95 PP (Q)                                                           105                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          25  33  66  394                                  2nd: 5A95 PP (NQ)                                                          106                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        46  >122                                                                              262 270                                  2nd: 5A95 PP (Q)                                                           107                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        49  122 262 239                                  2nd: 5A95 PP (NQ)                                                          108                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         7   17  41  176                                  2nd: 1550P PE (Q)                                                          109                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         17  33  41  239                                  2nd: 1550P PE (NQ)                                                         110                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          17  33  65  270                                  2nd: 1550P PE (Q)                                                          111                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          17  33  66  239                                  2nd: 1550P PE (NQ)                                                         112                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         7   17  262 176                                  2nd: 1550P PE + 250 ppm Mn + 2% OA (Q)                                     113                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         17  17  41  89                                   2nd: 1550P PE + 250 ppm Mn + 2% OA (NQ)                                    114                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        33  47  140 270                                  2nd: 5A95 PP + 250 ppm Mn + 2% OA (Q)                                      115                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        49  33  262 239                                  2nd: 5A95 PP + 250 ppm Mn + 2% OA (NQ)                                     116                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         39  39  67  245                                  2nd: 5A95 PP (Q)                                                           117                                                                              1st: 5A95 PP/1500P PE (1:1) + 250 ppm Mn + 2% OA,                                                          47  89  119 245                                  2nd: 5A95 PP (Q)                                                           118                                                                              1st: 5A95 PP/1550P PE (1:1) + 50 ppm Mn + 2% OA,                                                           47  67  111 215                                  2nd: 1550P PE (Q)                                                          119                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         29  39  68  215                                  2nd: 1550P PE (Q)                                                          120                                                                              1st: 5A95 PP/1550P PE (3:1) + 250 ppm Mn + 2% OA,                                                          29  68  69  245                                  2nd: 1550P PE (Q)                                                          121                                                                              1st: 5A95 PP/Quantum PE (1:1) + 250 ppm Mn + 2% OA,                                                        39  67  111 245                                  2nd: 1550P PE (Q)                                                          __________________________________________________________________________

Table 10 shows among other things that two-layer polyolefin films,wherein one of the layers does not contain the prodegradant system ofthe present invention, will oxidatively degrade under a variety ofconditions, including simulated composting conditions. In fact,degradation for such films occurs at comparable rates with those filmsthat contain the prodegradant system in all layers (e.g. Example filmNos. 112-115). Furthermore, radiation degradation-resistant films formedof mesophase propylene-based materials can be made to degrade atcomparable rates to the same films formed from crystalline polypropyleneusing the prodegradant system of the present invention (compare e.g.Example film Nos. 102 versus 103, and 108 versus 109).

EXAMPLES 122-142

Two-layer films were prepared using the same methods and materials asExamples 102-121, except that the first layer of each film wasapproximately 1.00 mil (51μ) thick, and the second layer was alsoapproximately 1.00 mil (51μ) thick, for a total film thickness ofapproximately 2 mil (51μ). Example films 122-142 were tested under thesame condition as for Examples 102-121. The specific composition andtime to embrittlement in hours for each of the Example films is shown inTable 11 below.

                                      TABLE 11                                    __________________________________________________________________________       Composition of layers        70° C.                                                                     60° C.                                                                     49° C.                                                                     60° C.                     Ex.                                                                              1st layer = 1.00 mil (25μ) thick                                                                        Hrs.                                                                              Hrs.                                                                              Hrs.                                                                              Hrs.                              No.                                                                              2nd layer = 1.00 mil (25μ) thick                                                                        Dry Dry Dry Wet                               __________________________________________________________________________    122                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        7   25  41  270                                  2nd: 5A95 PP + 250 ppm Mn + 2% OA (Q)                                      123                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        13  33  66  233                                  2nd: 5A95 PP + 250 ppm Mn + 2% OA (NQ)                                     124                                                                              1st: 1550P PP + 250 ppm Mn + 2% OA,                                                                        7   25  41  176                                  2nd: 1550P PE + 250 ppm Mn + 2% OA                                         125                                                                              1st 1550P PP + 250 ppm Mn + 2% OA,                                                                         13  25  41  145                                  2nd: 1550P PE + 250 ppm Mn + 2% OA (NQ)                                    126                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          17  47  66  239                                  2nd: 1550P PE (Q)                                                          127                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          13  33  66  145                                  2nd: 1550P PE (Q)                                                          128                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         17  17  41  176                                  2nd: 1550P PE (Q)                                                          129                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         13  33  42  239                                  2nd: 1550P PE (NQ)                                                         130                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        73  >72 163 394                                  2nd: 5A95 PP (Q)                                                           131                                                                              1st: 1550P PE + 250 ppm Mn + 2% OA,                                                                        73  144 262 270                                  2nd: 5A95 PP (NQ)                                                          132                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          33  47  94  --                                   2nd: 5A95 PP (Q)                                                           133                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Kn + 2% OA,                                                          25  72  94  945                                  2nd: 5A95 (NQ)                                                             134                                                                              1st: 5A95 PP + 250 ppm Mn + 29 OA,                                                                         17  47  93  409                                  2nd: 5A95 PP (Q)                                                           135                                                                              1st: 5A95 PP + 250 ppm Mn +  2% OA,                                                                        33  47  65  394                                  2nd: 5A95 PP (Q)                                                           136                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         47  47  137 245                                  2nd: 5A95 PP (Q)                                                           137                                                                              1st: 5A95 PP/1550P PE (1:1) + 50 ppm Mn + 2% OA,                                                           3   69  89  245                                  2nd: 1550P PE (Q)                                                          138                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                         29  39  89  245                                  2nd: 1550P PE (Q)                                                          139                                                                              1st: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                                                          39  90  91  245                                  2nd: 1550P PE (Q)                                                          140                                                                              1st: 5A95 PP/1550P PE (1:3) + 250 ppm Mn + 2% OA,                                                          67  119 211 245                                  2nd: 1550P PE (Q)                                                          141                                                                              1st: 5A95 PP/1550P PE (3:1) + 250 ppm Mn + 2% OA,                                                          29  39  67  245                                  2nd: 1550P PE (Q)                                                          142                                                                              1st: 5A95 PP/Quantum PE (1:1) + 250 ppm Mn + 2% OA,                                                        29  47  92  245                                  2nd: 1550P PE (Q)                                                          __________________________________________________________________________

The films shown in Table 11 demonstrate analogous degradation results tothose of Example films 102-121, Table 10. In addition, the data alsoshow that even when the non-prodegradant containing layer of thetwo-layer films is as thick as the prodegradant containing layer, theoverall films still oxidatively degrade under a variety of conditions,including simulated composting conditions. In fact, degradation forthese films occurs at comparable rates with films of Examples 102-122,wherein the non-prodegradant containing layer is seven times thinnerthan the prodegradant containing layer.

EXAMPLES 143-152

Three-layer films were prepared using the same methods and materials asExamples 102-121. Additional polymers used include Shell polybutyleneresin No. 400 (Shell Chemical Co.) and Vinex™ polyvinylalcohol resin No.1003 (Air Products, Allentown, Pa.). The first layer of each film wasapproximately 0.25 mil (6μ) thick, the second layer was approximately1.50 mil (38μ) thick, and the third layer was approximately 0.25 mil(6μ) thick, for a total film thickness of approximately 2 mil (51μ).Example films 143-152 were tested under the same condition as forExamples 102-121. The specific composition and time to embrittlement inhours for each of the Example films is shown in Table 12 below.

                                      TABLE 12                                    __________________________________________________________________________       Composition of layers                                                         1st layer = 0.25 mil (6μ) thick                                                                       70° C.                                                                     60° C.                                                                     49° C.                                                                     60° C.                       Ex.                                                                              2nd layer = 1.50 mil (38μ) thick                                                                      Hrs.                                                                              Hrs.                                                                              Hrs.                                                                              Hrs.                                No.                                                                              3rd layer = 0.25 mil (6μ) thick                                                                       Dry Dry Dry Wet                                 __________________________________________________________________________    143                                                                              1st: 1550P PE,             8   28  52  312                                    2nd: 5A95 PP + 250 ppm Mn + 2% OA,                                            3rd: 1550P PE (NQ)                                                         144                                                                              1st: 1550P PE,             25  47  94  409                                    2nd: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                             3rd: 1550P PE (NQ)                                                         145                                                                              1st: 5A95 PP,              33  122 290 825                                    2nd: 1550P PE + 250 ppm Mn + 2% OA,                                           3rd: 1550P PE (NQ)                                                         146                                                                              1st: 5A95 PP,              33  47  93  611                                    2nd: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                             3rd: 5A95 PP (NQ)                                                          147                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                       33  33  141 270                                    2nd: 1550P PE + 250 ppm Mn + 2% OA,                                           3rd: 5A95 PP + 250 ppm Mn + 2% OA (NQ)                                     148                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                       25  47  66  360                                    2nd: 5A95 PP/1550P PE (1:1) + 250 ppm Mn + 2% OA,                             3rd: 5A95 PP + 250 ppm Mn + 2% OA (NQ)                                     149                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                       25  33  41  89                                     2nd: 5A95 PP/Vintex 1003 (1:1),                                               3rd: Vinex 1003 (Q)                                                        150                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                       33  25  94  360                                    2nd: 400 PB/Vinex 1003 (1:1),                                                 3rd: Vinex 1003 (Q)                                                        151                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                       25  47  87  89                                     2nd: 400 PB                                                                   3rd: Vinex 1003 (Q)                                                        152                                                                              1st: 5A95 PP + 250 ppm Mn + 2% OA,                                                                       33  47  116 409                                    2nd: Vinex 1003/5A95 PP/400 PB (2:1:1)                                        3rd: Vinex 1003 (Q)                                                        __________________________________________________________________________

Table 12 shows among other things that three-layer films, such asExample film No. 143, that contain two layers without the prodegradantsystem, degrade at comparable rates to an analogous two-layeredstructure (i.e. Example film No. 109) containing only one layer withoutthe prodegradant system of the present invention. Furthermore, barrierfilm structures using a Vinex™ poly vinyl alcohol resin No. 1003 as agas barrier layer (i.e. Example films Nos. 149-152) degrade and compostwithin the requirements of the present invention.

EXAMPLES 153-154, AND COMPARATIVE EXAMPLES 155-156

The crystalline structure, or mesomorphous structure, for twosingle-layer films, and two five-layered barrier films containingpolypropylene polymer was determined by wide-angle x-ray diffraction(WAXD). The single layer films were formed as described above from Finapolypropylene resin No. 3576 (Fina Oil and Chemical Co.) containing theprodegradant system of the present invention at a film thickness ofapproximately 100μ. Example film No. 153 was quenched (Q) afterextrusion on a casting roll maintained at 10° C., so as to formpredominantly mesomorphous polypropylene, while Comparative Example filmNo. 155 was cast onto a roll maintained at 66° C. (NQ), thereby yieldingcrystalline polypropylene structure.

The five-layered barrier films were prepared as described above, exceptthat 3 extruders, and a 5-layer Cloeren™ feedblock (Cloeren Company,Orange, Tex.) connected to a single manifold film extrusion die wereutilized to form the films. The barrier films were generally coextrudedat a total film thickness of about 75μ, including a core layer of EVAL™brand ethylene vinyl alcohol (EVOH) resin No. 10A (Evalca Inc.; approx.8μ), followed by opposing polypropylene-based adhesive layers of Admer™resin No. QF551A (Mitsui Plastics, Inc.), and finally by opposing layersof Fina polypropylene resin No. 3576 with the prodegradant system of thepresent invention incorporated therein. The construction of Example film154 was quenched at 10° C., while that of Comparative Example film 156was cast at 66° C.

The specific constructions of Example films 153-154, and ComparativeExample films 155-156 are shown in Table 13. In addition, graphicalillustrations of the WAXD scans for each of the Example and ComparisonExample films are shown in FIGS. 1 through 4 herein. The mesophase form(i.e., mesomorphous polypropylene) is clearly shown in FIGS. 1 and 2. Incontrast, FIGS. 3 and 4 show the sharp peaks associated with crystallinepolybutylene.

                  TABLE 13                                                        ______________________________________                                        Specific film constructions of Example films 153-154, and                     Comparative Example films 155-156, and structure                              of the films as determined by WAXD                                            (Meso = mesomorphic, Crys = crystalline).                                     Ex.                                                                           No.  Film Composition           WAXD                                          ______________________________________                                        153  3576 PP + 250 ppm Mn +     Meso                                               2% OA (Q)                                                                154  1st layer: 3576 PP + 250 ppm Mn +                                                                        Meso                                               2% OA (Q)                                                                     2nd layer: ADMER ™ QF551A                                                  3rd layer: EVAL ™ 105A (EVOH)                                              4th layer: ADMER ™ QF551A                                                  5th layer: 3576 PP + 250 ppm Mn +                                             2% OA (Q)                                                                155  3576 PP + 250 ppm Mn + 2% OA (NQ)                                                                        Crys                                          156  1st layer: 3576 PP + 250 ppm Mn +                                                                        Crys                                               2% OA (NQ)                                                                    2nd layer: ADMER ™ QF551A                                                  3rd layer: EVAL ™ 105A (EVOH)                                              4th layer: ADMER ™ QF551A                                                  5th layer: 3576 PP + 250 ppm Mn +                                             2% OA (NQ)                                                               ______________________________________                                    

EXAMPLES 157-161

Five, five-layered barrier films were made according to the same methodsas for the films Example 154 and Comparative Example 156. In addition tothe polymers utilized in Example 154 and Comparative Example 156,several of the barrier films of Examples 157-161 also used Shellpolybutylene resin No. 0400 (Shell Chemical Co.), PRIMACOR™ brandethylene acrylic acid resin No. 3340 (Dow Chemical Co.), QUANTUM™ brandethylene vinyl acetate resin No. UE656-033 (Quantum Chemical Co.). Inaddition to the prodegradant system of the present invention, Examplefilm 161 also incorporated IRGANOX™ brand antioxidant No. 1010(Ciba-Geigy, Inc.) into its outer layers (i.e. the first and fifthlayers). The specific constructions of Example films 157-161 are shownin Table 14 below.

                  TABLE 14                                                        ______________________________________                                        Specific film constructions of Example films 157-161.                         Ex.                                                                           No.  Film composition for each Layer                                          ______________________________________                                        157  1st layer: 3576 PP/0400 PB (1:1) + 250 ppm Co + 2% OA                         (NQ)                                                                          2nd layer: ADMER ™ QF551A                                                  3rd layer: EVAL ™ 105A (EVOH)                                              4th layer: ADMER ™ QF551A                                                  5th layer: 3576 PP/0400 PB (1:1) + 250 ppm Co + 2% OA                         (NQ)                                                                     158  1st layer: 3576 PP/0400 PB/UE656-033 EVA (3:3:2) +                            250 ppm Mn + 2% OA (Q)                                                        2nd layer: ADMER ™ QF551A                                                  3rd layer: EVAL ™ 105A (EVOH)                                              4th layer: ADMER ™ QF551A                                                  5th layer: 3576 PP/0400 PB/UE656-033 EVA (3:3:2) +                            250 ppm Mn + 2% OA (Q)                                                   159  1st layer: 3576 PP/0400 PB/3340 EAA (3:3:2) + 250 ppm                         Mn + 2% OA (Q)                                                                2nd layer: ADMER ™ QF551A                                                  3rd layer: EVAL ™ 105A (EVOH)                                              4th layer: ADMER ™ QF551A                                                  5th layer: 3576 PP/0400 PB/3340 EAA (3:3:2) + 250 ppm                         Mn +  2% OA (Q)                                                          160  1st layer: 3576 PP/0400 PB (3:1) + 250 ppm Mn + 2%                            OA (Q)                                                                        2nd layer: ADMER ™ QF551A                                                  3rd layer: EVAL ™ 105A (EVOH)                                              4th layer: ADMER ™ QF551A                                                  5th layer: 3576 PP/0400 PB (3:1) + 250 ppm Mn +                               2% OA (0)                                                                161  1st layer: 3576 PP/0400 PB (1:1) + 250 ppm Mn +                               2% OA + Irganox 1010 (Q)                                                      2nd layer: ADMER ™ QF551A                                                  3rd layer: EVAL ™ 105A (EVOH)                                              4th layer: ADMER ™ QF551A                                                  5th layer: 3576 PP/0400 PB (1:1) + 250 ppm Mn +                               2% OA + IRGANOX ™ 1010 (Q)                                            ______________________________________                                    

Resistance to permeation of oxygen and moisture vapor was measured forthe multilayered barrier films of Examples 157-161. Oxygen transmissionrate (O₂ TR) was determined using an Ox-Tran™ 1000H machine (Mocon,Inc., Minneapolis, Minn.). O₂ TR was collected at 25° C. and zeropercent (0%) relative humidity. A square sample of each multilayer filmwas placed in the testing cell of the Ox-Tran™ oxygen permeabilitytester. Two samples of each film were tested in adjacent cells. Sincethe Ox-Tran™ 1000H machine has ten test cells, up to five films could beexamined at any one time.

Each cell was purged for at least 24 hours with a "carrier" gas ofnitrogen containing 1-3% hydrogen prior to testing, to remove anyresidual oxygen in the sample, cell and system. After purging wascompleted, a sample of the gases in each cell was tested for residualoxygen content or oxygen "leak rate". The leak rate value determined ateach cell was used as the cell's residual oxygen baseline.

Next, each cell was conditioned for another 24 hours by passing 100%oxygen over one side of the sample. Oxygen on the other side of thesample was measured after this conditioning period. This total oxygencontent included the amount of oxygen which permeated through the filmplus any residual oxygen in the system. To obtain oxygen transmissionrate through the film, the leak rate value was subtracted from the totaloxygen measured.

Oxygen transmission rate data was collected for each film at 25° C. and0% relative humidity. The values reported are the average of ratesdetermined for two samples. Since oxygen transmission rate is inverselyproportional to thickness, all values were normalized to a standard gasbarrier layer thickness of 25μ by multiplying the oxygen transmissionrate value by the ratio of barrier layer thickness to 25μ.

Moisture vapor transmission rate (MVTR) for the Example films wasdetermined using a Permatran™-W6 (Mocon, Inc., Minneapolis, Minn.). MVTRdata was collected at 38.6° C. and one-hundred percent (100%) relativehumidity. The reported values are the average of the values obtained forat least three samples of each Example film. Since MVTR is inverselyproportional to thickness, all values were normalized to a standardmoisture barrier layer thickness of 25μ (microns) by multiplying theMVTR value by the ratio of moisture barrier layer thickness (being thesum of the moisture barrier and adhesive layer thicknesses, as reportedin Table 3 herein) to 25μ. The oxygen transmission rates (O₂ TR) andmoisture vapor transmission rates (MVTR) for Examples 157-161 arereported in Table 15. These rates demonstrate good oxygen and moisturebarrier properties for the Example barrier films of the presentinvention.

                  TABLE 15                                                        ______________________________________                                        Oxygen transmission rates (O.sub.2 TR), as expressed in                       cc/m.sup.2 /day-atmosphere, and moisture vapor                                transmission rates (MVTR), as expressed in                                    g/m.sup.2 /day-atmosphere, for Examples 157-161.                                     Casting                                                                       Roll                                                                   Ex.    Temp.       O.sub.2 TR  MVTR                                           No.    (°C.)                                                                              (cc/m.sup.2 /d-atm)                                                                       (g/m.sup.2 /d-atm)                             ______________________________________                                        157    66          38.2        5.7                                            158    10          3.2         9.3                                            159    10          4.7         6.9                                            160    10          6.8         --                                             161    10          8.4         --                                             ______________________________________                                    

The various modifications and alterations of this invention will beapparent to those skilled in the art without departing from the scopeand spirit of this invention, and this invention should not berestricted to that set forth herein for illustrative purposes.

What is claimed is:
 1. A degradable multilayered structurecomprising:(a) a first layer of a polyolefin polymer containing aprodegradant system comprising from about 5 ppm to about 2000 ppm of atransition metal in the form of a salt; and (b) a second layer of apolyolefin polymer contacting the first layer of the multilayeredstructure; wherein the polyolefin polymer of the first layer, the secondlayer, or the first and second layers comprises a quenched mesophasepropylene-based material, wherein said multilayered structure isradiation-resistant.
 2. A degradable multilayered structure according toclaim 1, wherein at least one of the polyolefin polymers is selectedfrom the group consisting of polypropylene polymer, polyethylenepolymer, polybutylene polymer, and combinations thereof.
 3. A degradablemultilayered structure according to claim 1, wherein the ratio of thethickness of the first layer to the thickness of the second layer isfrom about 1:10 to about 1000:1.
 4. A degradable multilayered structureaccording to claim 1, wherein the ratio of the thickness of the firstlayer to the thickness of the second layer is from about 1:1 to about10:1.
 5. A degradable multilayered structure according to claim 1,wherein the mesophase propylene-based material is selected from thegroup consisting of mesomorphous polypropylene, a mesopolymer blend, amesocopolymer, and combinations thereof.
 6. A degradable multilayeredstructure according to claim 1, wherein the mesophase propylene-basedmaterial of the second layer contains the prodegradant system.
 7. Adegradable multilayered structure according to claim 1, furthercomprising a third layer of a polyolefin polymer contacting the surfaceof the first layer of the multilayered structure opposite from thesurface contacted by the second layer of the multilayered structure. 8.A degradable multilayered structure according to claim 7, wherein theratio of the thickness of the first layer to the thickness of the thirdlayer is from about 1:10 to about 1000:1.
 9. A degradable multilayeredstructure according to claim 7, wherein the ratio of the thickness ofthe first layer to the thickness of the third layer is from about 1:1 toabout 10:1.
 10. A degradable multilayered structure according to claim7, wherein the polyolefin polymer of the third layer comprises amesophase propylene-based material selected from the group consisting ofmesomorphous polypropylene, a mesopolymer blend, a mesocopolymer, andcombinations thereof.
 11. A degradable multilayered structure accordingto claim 1, further comprising a layer of a naturally biodegradablepolymer contacting the first, the second layer, or the first and secondlayers of the multilayered structure.
 12. A degradable multilayeredstructure according to claim 1, wherein the structure will oxidativelydegrade to embrittlement within about 14 days at a temperature of about49° C.
 13. A degradable multilayered structure according to claim 1,wherein the transition metal is selected from the group consisting ofcobalt, manganese, copper, cerium, vanadium and iron.
 14. A degradablemultilayered structure according to claim 13 wherein the prodegradantsystem further comprises an auto-oxidative component.
 15. A degradablemultilayered structure according to claim 14, wherein the auto-oxidativecomponent is selected from the group consisting of a fatty acid, asubstituted fatty acid, a derivative of a fatty acid, and combinationsthereof.
 16. A degradable multilayered structure according to claim 15,wherein the fatty acid has 10 to 22 carbon atoms.
 17. A degradablemultilayered structure according to claim 16, wherein the auto-oxidativecomponent comprises from about 0.1 to about 10 weight percent, based onthe total weight of the first layer, and provides at least about 0.1weight percent of unsaturated species and at least about 0.1 weightpercent of free acid species in the first layer.
 18. A degradablemultilayered structure according to claim 17, wherein the fatty acidcomprises an unsaturated fatty acid.
 19. A degradable multilayeredstructure according to claim 17, wherein the auto-oxidative componentcomprises an admixture of saturated fatty acids and unsaturated fattyacid esters.
 20. A degradable multilayered structure according to claim18, wherein the unsaturated fatty acid substantially comprises specieshaving two or more double bonds.
 21. A degradable multilayered structureaccording to claim 17, wherein the structure will oxidatively degrade toembrittlement within 14 days at 60° C. and a relative humidity of atleast 80%.
 22. A degradable multilayered structure according to claim 1,wherein the transition metal is present at a concentration of from about25 to about 500 parts per million.
 23. A degradable multilayeredstructure according to claim 1, wherein the first layer the secondlayer, or the first and second layer, further comprises an anti-oxidantat a concentration of from about 0.02 to about 0.2 weight percent.
 24. Adegradable multilayered structure according to claim 1, wherein thefirst layer, the second layer, or the first and second layers furthercomprise a naturally biodegradable polymer at a concentration of fromabout 5 to about 50 weight percent.
 25. A degradable multilayeredstructure according to claim 1, wherein the structure comprises a tube,a pouch, a bag, a tape, or a transdermal drug delivery patch.
 26. Adegradable multilayered barrier film comprising:(a) a gas barrier layerof a chlorine-free, naturally biodegradable polymer, the gas barrierlayer being substantially impermeable to oxygen gas; and (b) a moisturebarrier layer of a quenched mesophase propylene-based materialcontacting the gas barrier layer, and containing a prodegradant systemcomprising from about 5 ppm to about 2000 ppm of a transition metal inthe form of a salt, wherein said multilayered film isradiation-resistant.
 27. A multilayered barrier film according to claim26, wherein the chlorine-free, naturally biodegradable polymer is avinyl-alcohol containing polymer.
 28. A multilayered barrier filmaccording to claim 27, wherein the vinyl-alcohol-containing polymer isselected from the group consisting of ethylene vinyl alcohol copolymer,poly(vinyl alcohol) copolymer, and combinations thereof.
 29. Amultilayered barrier film according to claim 26, wherein thechlorine-free, naturally biodegradable polymer exhibits a permeabilityto oxygen gas of less than about 100 cc/m² /d-atm at 25° C. and 0%relative humidity.
 30. A multilayered barrier film according to claim26, wherein the chlorine-free, naturally biodegradable polymer exhibitsa permeability to oxygen gas of less than about 30 cc/m² /d-atm at 25°C. and 0% relative humidity.
 31. A multilayered barrier film accordingto claim 26, wherein the mesophase propylene-based material is selectedfrom the group consisting of mesomorphous polypropylene, a mesopolymerblend, a mesocopolymer, and combinations thereof.
 32. A multilayeredbarrier film according to claim 26, wherein the transition metal isselected from the group consisting of cobalt, manganese, copper, cerium,vanadium and iron.
 33. A multilayered barrier film according to claim26, further comprising a layer of a polyolefin polymer containing theprodegradant system contacting the gas barrier layer.
 34. A multilayeredbarrier film according to claim 33, wherein the polyolefin polymer isselected from the group consisting of polypropylene polymer,polyethylene polymer, polybutylene polymer, and combinations thereof.35. A multilayered barrier film according to claim 33, wherein thepolyolefin polymer comprises a mesophase propylene-based materialselected from the group consisting of mesomorphous polypropylene, amesopolymer blend, a mesocopolymer, and combinations thereof.
 36. Amultilayered barrier film according to claim 26, further comprising alayer of a polyolefin polymer contacting the moisture barrier layer. 37.A multilayered barrier film according to claim 26, wherein theprodegradant system further comprises an auto-oxidative componentcomprising a fatty acid, a substituted fatty acid, a derivative of afatty acid, or combinations thereof.
 38. A multilayered barrier filmaccording to claim 26, wherein the barrier film will oxidatively degradeto embrittlement within about 14 days at a temperature of about 49° C.39. A compostable multilayered barrier film comprising:(a) a gas barrierlayer of a chlorine-free, naturally biodegradable polymer, the gasbarrier layer being substantially impermeable to oxygen gas; and (b) amoisture barrier layer of a quenched mesophase propylene-based materialcontacting the gas barrier layer, the quenched mesophase materialcontaining a prodegradant system of an auto-oxidative componentcomprising a fatty acid, substituted fatty acid or derivatives, orblends thereof, the fatty acid having 10 to 22 carbon atoms, saidauto-oxidative component being at between about 0.1 to 10 weight percentbased on the total composition wherein the auto-oxidative componentprovides at least 0.1 weight percent of unsaturated species and at least0.1 weight percent of free acid species in the total composition, andfrom 5 to 2000 ppm of a transition metal in the form of a salt whereinthe transition metal is selected from the group consisting of cobalt,manganese, copper, cerium, vanadium and iron, wherein said multilayeredfilm is radiation-resistant.
 40. A compostable multilayered barrier filmaccording to claim 39, wherein the chlorine-free, naturallybiodegradable polymer is a vinyl-alcohol containing polymer selectedfrom the group consisting of ethylene vinyl alcohol copolymer,poly(vinyl alcohol) copolymer, and combinations thereof.
 41. Acompostable multilayered barrier film according to claim 39, wherein thechlorine-free, naturally biodegradable polymer exhibits a permeabilityto oxygen gas of less than about 100 cc/m² /d-atm at 25° C. and 0%relative humidity.
 42. A compostable multilayered barrier film accordingto claim 39, wherein the naturally biodegradable polymer of the gasbarrier layer comprises ethylene vinyl alcohol copolymer containing theprodegradant system.
 43. A compostable multilayered barrier filmaccording to claim 39, wherein in a film form the film will oxidativelydegrade to embrittlement within about 14 days at a temperature of about60° C. and a relative humidity of at least about 80%.
 44. A degradable,radiation-resistance composition comprising a quenched mesophasepropylene-based material containing a prodegradant system comprisingfrom about 5 ppm to about 2000 ppm of a transition metal in the form ofa salt.
 45. A degradable composition according to claim 44, wherein thetransition metal is selected from the group consisting of cobalt,manganese, copper, cerium, vanadium and iron.
 46. A degradablecomposition according to claim 44, wherein the prodegradant systemfurther comprises an auto-oxidative component comprising a fatty acid, asubstituted fatty acid, a derivative of a fatty acid, or combinationsthereof.
 47. A degradable composition according to claim 44, wherein ina film form, the composition will oxidatively degrade to embrittlementwithin about 14 days at a temperature of about 49° C.
 48. A degradablecomposition according to claim 44, wherein the composition comprises afilm, a fiber, a microfiber, or a tube.
 49. A method of containing aperishable material with a degradable packaging film comprising:(a)providing a degradable multilayered packaging film comprised of a firstlayer of a polyolefin polymer containing a prodegradant systemcomprising from about 5 ppm to about 2000 ppm of a transition metal inthe form of a salt, and a second layer of a polyolefin polymer, whereinthe polyolefin polymer of the first layer, the second layer or the firstand second layers comprises a quenched mesophase propylene-basedmaterial, wherein said multilayered film is radiation-resistant; and (b)contacting the perishable material with the second layer of thepackaging film, wherein the second layer serves to prevent the dispersalof the prodegradant system from the first layer of the packaging film tothe perishable material prior to disposal of the packaging film.
 50. Amethod of forming a degradable, radiation resistant articlecomprising:(a) extruding a propylene-based material containing aprodegradant system comprising from about 5 ppm to about 2000 ppm of atransition metal in the form of a salt to form an extrudate; and (b)quenching the extrudate immediately after extruding to provide aradiation-resistant article of a mesophase propylene-based materialcontaining said prodegradant system therein.
 51. A method of forming adegradable, radiation resistant article according to claim 50, furthercomprising, coextruding a chlorine-free, naturally biodegradable polymerthat is substantially impermeable to oxygen gas along with thepropylene-based material containing the prodegradant system to form amultilayered extrudate, and quenching the multilayered extrudateimmediately after extruding to form a multilayered article having atleast one layer of a mesophase propylene-based material containing theprodegradant system proximate at least one layer of a chlorine-free,naturally biodegradable polymer.
 52. A method of using a degradablemultilayered film as a barrier film comprising:(a) providing adegradable multilayered film comprised of a gas barrier layer of achlorine-free, naturally biodegradable polymer, the gas barrier layerbeing substantially impermeable to oxygen gas, and a moisture barrierlayer of a quenched mesophase propylene-based material contacting thegas barrier layer, the quenched mesophase propylene-based materialcontaining a prodegradant system comprising from about 5 ppm to about2000 ppm of a transition metal in the form of a salt, wherein saidmultilayered film is radiation-resistant; and (b) interposing thedegradable multilayered film between a protected environment and anexternal environment such that gases and moisture cannot substantiallypass through the degradable multilayered film.
 53. A method of using adegradable multilayered film as a barrier film according to claim 52,wherein the degradable multilayered film comprises a packaging filmcontaining a perishable product in the protected environment.
 54. Amethod of using a degradable multilayered film as a barrier filmaccording to claim 53, wherein the perishable product comprises a foodproduct or a pharmaceutical product.
 55. A method of using a degradablemultilayered film as a barrier film according to claim 52, wherein thecompostable multilayered film comprises a transdermal drug deliverypatch, medical tape, or an ostomy pouch.